PYC3704 EXAM PACK 2025

QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 1. A psychological theory is best defined as - - - - - S 1. a set of observations of human behavior 2. postulated relationships among constructs 3. statistical inferences based on measurements 2 Study guide: P99-100 2. A master’s student in psychology plans to study human consciousness, following the recent publication of Watson's theory about the nature of consciousness. The main aim of the research will probably be to empirically - - - - - 1. test predictions based on Watson's theory 2. test Watson's theory so that it can be accepted or rejected as a whole 3. study consciousness with a view to understanding, predicting and controlling it 2 3. Which of the following best describes "latent"? 1. observable 2. manifest 3. hidden 3 Study guide: P7 4. The (a) - - -variable has an effect on the (b) variable 1. (a) dependent (b) independent 2. (a) operational (b) measured 3. (a) independent (b) dependent Study guide: P8-9, 24 5. A psychologist conducts a study in which she measures the reaction times of students doing a psychometric test. She proceeds from the assumption that good reaction time is an indication of intelligence in this study 'intelligence' is the variable 1. operational 2. latent 3. manifest 3 Study guide: P7,11,18 6. In a study, the relationship between anxiety (high and low) and test performance (measured in terms of pass and fail) is considered A suitable hypothesis for the study can be viewed as - - - - - 1. a rule suggesting how the values of 'anxiety' may be related to the values of 'test performance' 2. correlation which was found between the variables 'anxiety' and 'test performance' 3. rules which operationalize the values of the variable’s 'anxiety' and 'test performance' 2 Study guide: P15, 71,99 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 3 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 7. A psychologist is conducting a study about the self-concepts S of university students. She makes the assumption that students' concepts of themselves can be used to predict their willingness to participate in class discussions. In order to be able to do a scientific study of this (a) ------ question, she would have to provide a (an) (b) - - - - - definition of the (c) -----called "self-concept" 1. (a) scientific (b) experimental (c) concept 2. (a) experimental (b) research (c) operational concept 3. (a) research (b) operational (c) construct 3 Study guide: P4 8. A construct can be regarded as a - - - - - 1. quantitative measurement of an human characteristic as revealed in a psychometric test 2. hypothetical aspect of humans that we wish to investigate 3. testable prediction derived from a theory of human behavior 2 Study guide: 9. Which statement about the aims of psychological research P6 is most accurate? 1. it is primarily aimed at gathering facts 2. it is mainly used to develop research hypotheses 3. its goal is to test psychological theories 2 Study guide: P2 10. Operational definitions enable us to - - - - - (a) make observations of constructs (b) link constructs to observable phenomena 1. (a) but not (b) 2. (b) but not (a) 3. both (a) and (b) 2 Study guide: P6-7, 5-16,24-26, 11. A researcher studies the relationship between gender and salary in a selected random sample of employees of a computer company. Select the option that is most appropriate. The study is a (a) - - - - - design, because it (b) - - - - - 1. (a) two-group (b). compares two samples of groups in a population 2. (a) one-group (b). compares a single sample on two continuous variables 3. (a) correlational (b). studies the correlation between two variables 3 Study guide: P2, 10- 11,140 12. Assume that a researcher believes that education plays a role in promotions. He decides to investigate this by using a sample of 100 employees at a company called Computer Solutions Inc. Which one of the following is the most appropriate way to formulate the research hypothesis? 1. Education is related to the promotion of employees at Computer Solutions inc 2. Employees with higher levels of education earn more than employees with lower levels of education at Computer Solutions inc 3. Employees with higher levels of education are more likely to be promoted at Computer Solutions inc than employees with lower education at corresponding post levels 2 Study guide: P129- 133 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 4 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 13. S If 10 000 students wrote a university admission test, 7000 passed (obtained 50% or more) and 400 obtained exactly 50%, what is the probability that a randomly selected student will fail the test? 1. 0.04 2. 0.7 3. 0.3 2 Study guide: P35-36 14. A class of 10 boys and 11 girls, including Lizzie and her friend Lebo, chooses a class representative by writing their names on slips of paper, putting these into one box and asking their teacher to draw one name blindly Which of the following is closest to the probability that EITHER Lizzie OR Lebo will be selected? 1. 0.002 2. 0.095 3. 0.182 2 Study guide: P29 15. The table presents a frequency count of the number of items that each person can remember out of a list of items, for a random sample of research participants. for a random sample of research participants if X is the number of items likely to be remembered by a randomly selected person, what would p(X > 7) be, if one calculated this probability using the relative frequency approach? 1. 0.07 2. 0.15 3. 0.32 2 Study guide: P86, 130- 132 16. What is the principal advantage of z scores? They enable one to - - - - - 1. compare a person's scores on tests with different means and standard deviations 2. transform a person's scores on different tests into comparable percentages 3. determine whether scores are normally distributed 2 Study guide: P53 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 5 17. Consider the following Table Subject Mean for Student X Mean for class Standard deviation for class A B C 50% 55% 60% 40% 50% 50% 5% 5% 10% In which subject did a student (indicated as Student X in the second column) do best, relative to the class? 1. A 2. B 3. C 2 Study guide: P55-60 18. The mean of the standard normal distribution equals - - - while its standard deviation equals - - 1. 2. 3. 2 Study guide: P52- 55 19. Study the histogram below of the exam marks (out of 60) of a group of students in the same class. (Note that the values on the horizontal axis are the class limits) Assume we use this histogram as a basis for making probability predictions Which of the following is the best estimate of the probability that a student's score will be between 40 and 60? 1. 0.3 2. 0.5 3. 0.7 1 Study guide: P29, 40,47 130-132 142-144 20. When a sample is randomly selected from a population, the sampling error depends on the - - - - - 1. the size of the sample 2. the size of the population 3. the population mean 2 Study guide: P60- 61 Questions 22 and 23 are based on the following scenario The mean mark obtained for a psychology assignment by all the students who completed it is 35, and the standard deviation 15. John received a mark of 45 for this psychology assignment S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 6 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 21. The asymptotic property of the normal curve refers to the S fact that - - - - - curve is bell-shaped endpoints of the normal curve never touches the horizontal axis left side of the curve is a mirror image of the right side 1 Study guide: P52 22. if the scores are transformed into a standard normal distribution, what would John's z-score for his assignment mark be? (Rounded to two places) 1. 0.67 2. 0.34 3. 0.16 2 Study guide: P55 23. Referring to the scenario above, what is the probability of John receiving his score of 45 or better if we can assume that the assignment scores are more or less normally distributed? (Select the best answer out of the options). 1. 0.7486 2. 0.6667 3. 0.2514 2 Study guide: P55-56 24. Mary received 25 marks for her psychology assignment. The mean mark for this assignment is 35, and the standard deviation is 10 What proportion of the students received higher marks than Mary? 1. 0.16 2. 0.84 3. 0.34 2 Study guide: P130- 140 25. Study the following figure of a normal curve for the distribution of a specific set of data For a random measurement x from this population, what is p(x<155)? 1. 0 84 2. 0.16 3. 0.50 1 Study guide: P163 26. Sibu is doing research on the IQ scores of the students Assuming that this IQ will on average be greater than that of the overall population, he states the following hypothesis H0 µ = 100 H1 µ > 100 After drawing a random sample of 50 students, Sibu finds that they have a mean IQ score of 107 and a standard deviation of 5 if it was the case that the null hypothesis is actually true, what would the expected mean of the sample be? 1. Around 100 2. Around 107 3. More than 100 2 Study guide: P81 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 7 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 27. The central limit theorem implies that, for large samples S from non-normal populations, - - - - - 1. the sampling distribution of the mean across samples will be approximately normal 2. the distribution of sample values will be approximately normal 3. the observed relative frequency of an event will approach its theoretical probability 1 Study guide: P60-61 28. When a statistical test yields a large p-value, which of the following statements is most likely to be correct? 1. The alternative hypothesis is probably true 2. The null hypothesis is probably true 3. The null hypothesis is probably false 2 Study guide: P81 29. Which of the following is likely to be specified in advance by the researcher, before any actual data are collected? 1. The effect size 2. The level of significance 3. The expected p-value under Ho 3 Study guide: P82-86 30. When two population means are compared, the p-value expresses the probability that a (n) 1. observed difference between the means is due to sampling error 2. difference found between the means is due to the alternative hypothesis 3. difference will be found between the means 2 Study guide: P87, P139 31. When doing a one-sample statistical test, the failure to reject H0 implies that a difference between the calculated sample mean and its expected value as predicted under Ho is due to - - - - - 1. the dependent variable 2. the independent variable 3. chance 3 Study guide: P86 32. The level of significance is the - - - - - 1. maximum allowable probability of Type II error 2. maximum allowable probability of Type I error 3. probability that not rejecting the null hypothesis would be an error 2 Study guide: P85 33. The null hypothesis is rejected if - - - - - 1. the p-value under H0 is smaller than the level of significance 2. the p-value under H1 is larger than the level of significance 3. the p-value is smaller than 0.5 or 0. 1 3 Study guide: P86-87 34. The power of a statistical test refers to the - - - - - 1. ability of the test to give small p-values 2. ability of the test to detect significant results 3. the sample size 2 Study guide: P85- 86 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 8 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 35. A Type I error occurs when - - - - - S 1. the null hypothesis is wrongly rejected 2. the null hypothesis is wrongly not rejected 3. the alternative hypothesis is wrongly rejected 1 Study guide: 82- 86 36. it is found that the larger the z, -test statistic value for a sample of a particular size, the smaller the p-value becomes - - - - - 1. as the standard error becomes smaller 2. but this would be merely as a consequence of a random effect 3. as the difference between the sample and population means becomes larger 2 Study guide: P85 37. Suppose one wants to limit the risk of a type II error by increasing the power of the test after the level of significance is fixed at 0.05 Which of the following can we do? (a) Increase the sample size (b) Decrease sampling error, measurement error, etc. 1. (a) but not (b) 2. (b) but not (a) 3. Both (a) and (b) are correct 3 Study guide:P8 2-86 38. The size of the level of significance depends on - - - - - 1. the calculated value of the test statistic 2. a definite value determined by the researcher 3. the p-value under Ho 2 Study guide: P84- 85 Questions 39 and 40 are based on the following scenario Peter is a human resource consultant and his boss asks him to test the employees in their company to determine if the level of negative attitude towards people with AIDS of these workers in some way differs from that of the general worker in South Africa. Suppose that on the basis of previous studies it is accepted that the mean negative attitude score on a particular scale of the population of workers in South Africa is 55 (the higher the score the more positive) and that the population standard deviation 39. Which of the following statements translates the research hypothesis into the appropriate statistical hypotheses? 1. H0 µ = 55 H1 µ < 55 2. H0 µ = 55 H1 µ > 55 3. H0 µ = 55 H1 µ at 55 3 Study guide: P11-18, 21-26 40. Peter finds that the workers in his company have a mean attitude score of 50 Which of the statistical test procedures below would be most appropriate to use? 1 A t-test for a single sample mean 2 A z-test for a single sample mean 3 A t-test for two sample means 2 Study guide: P6 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 9 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 41. Statistical hypotheses are statements about - - - - - S 1. population parameters 2. sample statistics 3. inferential statistics 1 Study guide: P75 Questions 42 and 43 are based on the following scenario An educational psychologist compares two groups of schoolchildren from urban and semi-urban areas on a language comprehension test. She manages to get a sample of 600 urban and 400 semi-urban children (matched for gender and age) to complete a test. She finds mean language comprehension scores of for the urban and semi-urban groups respectively. 42. The educational psychologist decides to do a t-test to compare the two sample means. Which of the following is the appropriate t-test statistic that she should calculate? 1. 2. 3. 2 Study guide: 43. The psychologist calculates the appropriate t-test to compare the two means, and the result is a t-statistic value of 2.67 She determines that this is significant on the 1% level. The researcher is however, concerned that the actual difference between the two-group means is fairly small, and that the significant result may be the consequence of the large sample sizes. What could she do to check whether this is significant results is meaningful in a practical sense? She should calculate the - - - - - 1. power of the test 2. effect size 3. standard error 2 Study guide: P6 44. Which one of the following alternative hypotheses requires a non-directional test of significance? 1. The mean anxiety score for boys is greater than that of girls 2. The mean verbal ability score for boys does not exceed that of girls 3. The correlation between test marks and examination marks is not the same for boys and girls 3 Study guide: P75 45. When applying a statistical test, if the p-value is smaller than the level of significance we --- the null hypothesis 1. accept 2. do not reject 3. reject 2 Study guide: P6 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 10 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 46. Consider the following statistical hypotheses S H0 µ = 50 H1= µ > 50 Suppose the two-tailed p-value is 0.0345 and the level of significance is set at 0.05 The sample mean was found to be 55 What is the value of the one-tailed or directional pvalue? 1. 0.0250 2. 0.0690 3. 0.0173 3 Study guide: P75 47. Suppose the level of significance is set at 0.05, and the appropriate p-value is calculated as 0.03 What is the probability that the researcher will be making a Type I error should he decide to reject H0 ? 1. 0.03 2. 0.05 3. More information is needed to calculate it 2 Study guide: P6 48. The p-value depends on - - - - - 1. the z-tables 2. the size of the test statistic 3. the null hypothesis statement 2 Study guide: P83-84 49. The difference score (d = x2 – x1) is used in the calculation of the ta-test statistic in the case of - - - 1. dependent samples 2. independent samples 3. both of the above 2 Study guide: P112,134- 136 50. When comparing two sample means from independent groups with a t-test, the size of the p-value with depend on the value of - - - - - 1. 2. 3. 1 Study guide: P83-84 51. Suppose you find that the value of a t-test statistic calculated for your research results when comparing two means is 3.0 and the appropriate p-value = 0.02. Which conclusion is appropriate? 1. Reject the null hypothesis if the level of significance was set at 0.01 2. Do not reject the null hypothesis if the level of significance was set at 0.05 3. Reject the null hypothesis if the level of significance was set at 0.05 2 Study guide: P114 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 11 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 52. S In which of the following cases can the scores on two variables not be regarded as independent? (a) The variables represent scores from persons ,in a control group and an experimental group, where each member of the two groups was matched on the basis of demographic variables like age and gender (b) The variables represent scores from the same persons measured on two occasions six months apart on the same test 1. (a) but not (b) 2. (b) but not (a) 3. Both (a) and (b) 3 Study guide: P8-9,24, 110-112 53. Cohen's d refers to a measure of the - - - - - 1. effect size 2. power of a test 3. difference between two means for dependent samples Study guide: P86- 87, 91, 116- 117 54. A large t-test statistic - - - - - 1. implies that the p-value will be large 2. implies that the p-value will be small 3. is unrelated to the size of the p-value 2 Study guide: P81 Questions 55 and 56 are based on the following scenario An educational psychologist investigates what effect extra classes where learners are taught reasoning skills would have on the performance of pupils in mathematics. The grade twelve learners in a specific school are divided into two groups One group of 20 pupils receives the extra classes in reasoning skills while a control group of 20 pupils receives singing lessons in the same period. The teacher calculates the increase or decrease in his or her mathematics performance for each of the 40 pupils based on a mathematics test before the extra classes and a second mathematics test after the extra classes for both groups. 55. Which research design is the teacher most likely to use? 1. A matched-pairs design 2. A two-sample design with independent groups 3. A two-sample design with dependent groups 2 Study guide: P100-106 56. The most appropriate statistical test to use to compare the two groups of learners with regard to the change in their mathematics test results would be the - - - - - 1. t-test for dependent groups 2. chi-square test 3. t-test for independent groups 3 Study guide: P100- 106 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 12 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 57. Which of the following assumptions are sufficient for a two- S sample t-test (even if the samples are relatively small)? 1. The sample standard deviations must be equal, but the distributions may be unknown 2. The data from both samples come from populations that are normally distributed, so the standard deviations need not be considered 3. The data from both samples come from populations that are normally distributed and the sample standard deviations are equal 3 Study guide: P115-116 58. A researcher suspects that social phobia is more common among females than among males She wants to test this by comparing the following hypotheses. H0 µ1 = µ2 H1 µ1 > µ2 Here µ1 indicates the average level of social phobia among females in the population (group 1) and µ2 is the average level of social phobia among males in the population (group 2) The researcher uses a 7- point scale to measure social phobia where a higher score implies a greater level of phobia, she draws random samples of females and males respectively, and gets the following average levels of social phobia scores for each group. What may she conclude? 1. Ho can be rejected. 2. H0 cannot be rejected. 3. No conclusion is possible before the relevant test statistic and p-value are calculated 3 Study guide: P114- 116 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 13 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 59. When would a statistician choose to do a t-test rather than a S z-test to compare a sample mean with a given population mean? 1 the sample standard deviation is unknown 2 The standard error is unknown 3 The population standard deviation is unknown 3 Study guide: P102-106 60. A researcher wants to determine whether the level of academic accomplishment that a student has reached is in any way related to the way in which the student approaches problem solving to do this, she plans to relate the exam marks of a group of undergraduate students to their results on a test that indicates problem-solving style Which is the independent variable? 1 problem-solving style 2 exam marks 3 accomplishment 3 Study guide: P7-9, 24 61. A politician asks his audience of 100 whether they will vote for him, and 60 say yes, He then delivers his speech and repeats the question Now 70 persons say yes. When analyzing these results, the two sets of answers should be regarded as - - - - - 1. dependent 2. independent 3. normally distributed 1 Study guide: P112 62. A researcher predicts that a motivational talk will improve the work performance of men. However, when testing this hypothesis, he finds that the mean work performance of his sample of 20 men is actually poorer after the motivational talk than before Based on these results, what statistical test should the researcher do to make a conclusion regarding the hypothesis possible? 1. A one-tailed statistical test is required 2. A two-tailed statistical test is required 3. No statistical test is required 1 Study guide: P75- 76 63. Which of the following does not represent a valid value for a Pearson's r ? 1. 0.00 2. 1.09 3. -0.99 2 Study guide: P133 64. As the sample size (n) increases - - - - - 1. a smaller value of the Pearson's correlation coefficient r will reach significance 2. a larger value of the Pearson's correlation coefficient r is required before the result will be significant 3. there are no implications for the significance of the value of the Pearson's correlation coefficient r 1 Study guide: P60- 61 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 14 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 65. A researcher wants to establish whether the type of S employment category that is filled by employees of a particular company (manager, middle manager, clerical worker, technical worker) is at all influenced by their gender (male or female). Which would be the most appropriate test to use? 1. The t-test for two independent samples 2. Pearson's correlation test statistic 3. The chi-square (x"2) test statistic 3 Study guide: P140 66. if there is no relationship at all between scores on two continuous variables, what would be the most the likely value of Pearson's correlation coefficient (r) be, out of the following? 1. -10 2. 05 3. 0.0 3 Study guide: P129- 130 67. The chi-square (x2) test statistic is used to compare - - - - - 1. the distribution of frequency data which was observed with the distribution of the data that is expected if the null hypothesis is true 2. the mean of a number of measurements with the mean value of the measurement in the general population as expected if the null hypothesis is true 3. the relationship between two variables which represent continuous measurements on two different constructs for a sample of observations from the same population 1 Study guide:P1 10, 140 68. A Pearson correlation of r = 0.23 is found. What kind of relationship between two variables X and Y does this represent? 1. As variable X grows smaller, variable Y gets smaller 2. As variable X grows larger, variable Y gets smaller 3. As variable X grows smaller, variable Y gets larger 1 Study guide: P134- 136 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 15 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR 69. A researcher wants to determine whether a relationship S exists between students' general level of anxiety and their exam results He presents each student from a sample of n = 150 students with a general anxiety scale Just before they are to write an important exam. The anxiety scale consists of 10 questions with 1 indicating low and 5 indicating high anxiety for each item, which are added together to produce an anxiety score. The exam gives a percentage score. Which of the following is the most appropriate test statistic to use to determine whether a relationship exists between the two variables (anxiety level and exam results)? 1. t-test 2. Pearson's r test statistic 3. chi-square test (x2) 2 Study guide: P86, 130- 132 70. The contingency table below indicates observed frequencies of gender (male or female) crossclassified with environment (urban or rural) of a particular sample of research participants. What would the expected frequency for rural males be if the frequencies are evenly distributed (i.e. if the null hypothesis of a chi-square (x2) test were true)? 1. 4 2. 2 3. 8 2 Study guide: P142- 144 October / November 2015 - End S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 16 May/June 2017 QUESTION A N S PAGE NR. COMMENTS 1. The term 'inference’ in psychological research refers to 1. the process of setting up a hypothesis as a relationship among variables 2. making a prediction or generalization based on existing information 3. the procedures for making a construct visible so that a measurement can be made 2 Study guide: P2 - An inference is a conclusion that follows from existing information, by generalising from the specific information to the general type of phenomenon, where the conclusion is not absolutely certain. So, in summary inferential statistics are techniques for making generalisations based on imperfect numeric data, where the conclusions have a high probability of being true, but you can never be completely certain. 2. In psychological research, a construct may be a (n) 1 measurement based on the careful observation of aspects of humans or human behavior 2. observation of an aspect of humans or human behavior which was operationalized in some way 3. hypothetical aspect of humans or human behavior which we wish to investigate 3 Study guide: P4 Constructs and their interrelations (how they affect each other, their patterns of interaction) are used in this way to develop theoretical explanations of why people behave in certain ways in certain contexts, or why mental phenomena appear to be as they are. 3. Which of the options below provides the best description of the main purpose of quantitative research in psychology? its purpose is to 1. develop theories that explain the relationships among observed aspects of human behavior and mental processes 2. develop predictions about human behavior of which we can be applied with absolute certainty 3. develop hypotheses about relationships that may exist among various constructs 3 Study guide: P1- 2 Psychology is a discipline that endeavors to collect information and develop theories about human behavior and mental processes. The aim is to establish facts that are related to psychological phenomena, that are valid and can be justified on scientific grounds. 4. Operationalizing a construct means to 1 find an explanation for the construct to explain why it appears as it is 2. make an educated guess on how it relates to other constructs 3. devise a systematic procedure to make the construct observable, in such a way that we can measure it 3 Study guide: P25 1.2.1& P4 1.2.2 'Operationalization' is where you make the construct (which is usually an abstract concept, so it is difficult to observe it clearly) visible by finding some suitable way to measure it. You need it to be able to test a hypothesis, but it is not in itself 'the process of forming a hypothesis'. The primary aim of operationalization is to describe a construct clearly and unambiguously so that it can be measured and tested in a research study. S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 17 QUESTION A N S PAGE NR. COMMENTS 5. Empirical knowledge is knowledge that is based on 1. careful reasoning 2. appropriate theories 3. the observation of events 3 Study guide: P2 All scientific knowledge begins with description of the phenomena being studied, based on careful observation. Knowledge based on observation of physical events is referred to as empirical knowledge (as distinct from knowledge based on contemplation, unexplained insights, mystical experiences or claims by authority figures). Use the following extract from a research proposal to answer Questions 6 to 8 “Generalised anxiety disorder (GAD) refers to a pattern of almost constant worry or tension, even when there is little or no apparent cause. Both genetic predisposition and stressors in the life of a particular patient is believed to contribute to this condition. The research will investigate whether the level of anxiety of persons diagnosed with GAD is actually reduced by psychotherapy. it is expected that patients receiving therapy will score lower on the Manifest Anxiety Scale than patients not receiving therapy " 6. Both genetic predisposition and stressors in the life of a particular patient is believed to contribute to this condition' is 1. the research hypothesis 2. a theory about the causes of GAD 3. a postulated relation between two constructs 2 Study guide: P4, 15, 18-19, 21-26 A theory is a well-established principle that has been developed to explain some aspect of the natural world. A theory arises from repeated observation and testing and incorporates facts, laws, predictions, and tested hypotheses that are widely accepted. In science, a theory is a framework for facts. It is some kind of description that tells you how the facts are connected, and why the facts are as they are (where the word 'facts' refers to things or events that were observed and described in a careful way). A theory is a network of relations among facts that were proposed to be true and explanations for observed phenomena in terms of constructs. 7. "Whether the level of anxiety of persons diagnosed with GAD is actually reduced by psychotherapy" describes 1. a theoretical prediction about the effect of psychotherapy 2. the operationalization of the construct 'anxiety’ 3. the hypothesis to be investigated 3 Study guide: P4 P15 P18-19 P21-26 8. The dependent variable is ______ and the independent variable is ______ 1. whether psychotherapy is received, the level of anxiety experienced by patients 2. the effectiveness of psychotherapy, the level of anxiety 3. the level of anxiety experienced by patients, whether or not psychotherapy is received 3 Study guide: P8- 9, 24,113- 116 The dependent variable is the one that is predicted or explained, and the independent variable is manipulated to see how it affects the dependent variable. The independent variable is that variable which affects the dependent variable; or, conversely, the dependent variable depends on the independent variable. S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 18 QUESTION A N S PAGE NR S QUESTION ANS A N S PAGE NR S 9. Mean, range, variance and standard deviation are examples of______ 1. inferential statistics 2. test statistics 3. descriptive statistics 3 Study guide: P10-11 A distinction exists between inferential statistics and descriptive statistics. Descriptive statistics refers to a set of quantities used to summarize aspects of numerical data. Examples that you may be familiar with are means, range, variance and standard deviation (see Appendix C for a quick introduction). These summary quantities are sometimes referred to as parameters. 10. A researcher would use a ______ to make a(n) ______ about the nature of the ______ 1. sample, inference, population 3. variable, prediction, construct 4. population, inference, sample 2 Study guide: P7 A construct that has been measured in some way produces a variable. A variable refers to a number that can take on any one of a range of possible values. They can be discrete (when only whole numbers like 1, 2, 3 are allowed) or continuous (what mathematicians refer to as 'real numbers'). In some cases, variables also take on values smaller than zero to produce negative numbers. So, the (visible) variable reflects the intensity of the underlying (invisible) construct, in terms of how it was measured. We say that the variable is manifest (it is visible in the sense that we can observe it) and the construct is latent (it is invisible in the sense that we need some way to make it appear). So, the latent construct is made manifest by the use of an appropriate measurement procedure. The dependent variable is the one that is predicted or explained, and the independent variable is manipulated to see how it affects the dependent variable. 11. A measurement that summarizes an aspect of a population is called a_____ while a measurement that describes the same aspect of a sample is called 1. construct, variable 2. parameter, statistic 3. statistic, parameter 2 Study guide: P14, 23 Parameters are values that summarize aspects of population data. While the word 'parameters' does refer to descriptive statistics, it does not refer to all descriptive statistics. it is used only for those descriptive statistics that relate to the population, not to those that describe aspects of the sample. A statistic is a sample measurement characteristic. A test statistic is the quantity you calculate (often by making use of sample statistics) to test a statistical hypothesis. When we refer to these test quantities, we always refer to the name in full -'test statistic', and when we use the term ‘statistic' on its own it refers to a descriptive statistic that describes an aspect of the sample data. S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 19 QUESTION A N S PAGE NR. COMMENTS 12. A ___ is a speculative statement about the relationship among ____, based on observations or expectations 2. hypothesis, statistics 3. theory, variables 4. hypothesis, constructs 3 Study guide: P1, 18-19 A research hypothesis is formed as a clear statement in terms of a relationship among the constructs (and the variables by which they are measured). it is a statement about a possible relationship among constructs that may explain some set of observations that one intends to investigate. Constructs: concepts that act as explanations for phenomena, events and behavior and are abstracted from observations. Theories: a theory is a frame of reference for facts that attempts to account for why things are as they are; a claim about how constructs are related to produce phenomena, which has been validated by research. 13. A jar contains 5 red, 8 blue, 3 green and 4 yellow marbles. What is the probability that a person who is blindfolded will choose a green marble purely at random? 1. 0.15 2. 0.33 3. 0.50 1 Study guide: P29 Number of possible outcomes = Total marbles = 20 (5+8+3+4) Number of favorable events = Pick one green marble = 3 p(E) = Number of favorable events Number of possible outcomes = 3 = 3/20 = 0.15 14. A class of 10 boys and 11 girls, including Mary and her friend Elizabeth, chooses a class representative by writing their names on slips of paper, putting these into a box and asking their teacher to draw one name blindly. What is the probability that either Mary or Elizabeth will be selected? 1. 1/11 2. 1/21 3. 2/21 3 Study guide: P29 Number of possible outcomes = Total kids = 21(10+11) Number of favorable events = Either Mary or Elizabeth = 2 p(E) = Number of favorable events Number of possible outcomes = 2/21 There 11 girls, the question is asking you which girl Mary or Elizabeth will be selected. Not the boys 15. Which statement best represents an application of the law of large numbers? if I flip a coin 1000 times, it will fall heads-up ______ 500 times 1. approximately 2. exactly 3. at least 1 Study guide: P31-32 The principle is called the law of large numbers, and it states the following: if an experiment is done repeatedly, and the outcomes are independent of one another, the observed proportion of favorable occurrences of an event will eventually approach its theoretical probability. The law states that a probability value should be seen as a theoretical limit on which the relative occurrence of an event (outcome) can be expected to converge over time in the long run. For example, in the above coin-flipping example, the probability of the coin coming up heads or tails on any flip is not influenced by the result of the previous flip. Each flip is independent of the other, and the theoretical probability of heads coming up remains the same, that is, p(heads) = 1/2 = 0.5. S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 20 QUESTION A N S W E R PAGE NR. COMMENTS 16. The expression "0.05 < p ≤ 0.10" should be interpreted as a probability value ______ 1. smaller than 0.05 and larger or equal to 0.10 2. halfway between 0.05 and 0.10 3. larger than 0.05 and smaller or equal to 0.10 3 Study guide: P33-34 Because probabilities fall in a range from 0.0 to 1.0 when expressed decimally, a probability can never be higher than 1or lower than 0. The general rule is written symbolically as follows: 0 ≤ p ≤ 1. Note that a probability can be 0, but to say that a probability is 0 is actually the same as saying that the event is impossible and can never happen. Likewise, to say that the probability of an event is 1is to assert that it is an absolute certainty. In actual practice, probabilities fall within these two extremes. You will typically encounter reference to probabilities in expressions such as ''p > 0.05''. This statement is interpreted as ''the probability value is higher than 0.05''. 17. Suppose that over the years 10 000 students wrote the examinations in PYC 3704-C and that 6000 of them passed, of which 300 obtained exactly 50%. This means that for randomly selected students the probability of obtaining exactly 50% is _ while the probability of obtaining 50% or more is___ 1. 0.60, 0.03 2. 0.05, 0.60 3. 0.03, 0.60 3 Study guide: P35-36 First equation: p(E) = Number of favorable events = 300 = 3 = 0.03 Number of possible outcomes =300/10000 = 0.03 Second equation: p(E) = Number of favorable events = 6000 = 6 = 0.6 Number of possible outcomes 10000 10 =6000/10000 = 0.060 18. During the interpretation of psychological measurements, the normal distribution is often ______ 1. adapted to fit the observed frequency distribution of scores 2. used as a theoretical model for interpreting the observed distribution of scores 3. used to calculate the relative frequency of observed scores 2 Study guide: P50 -51, 52-53 Many of the scores that we use are also clustered around the average and tail off to the ends of the distribution. Because it can be used to describe the distribution of many naturally or 'normally' occurring continuous variables, this type of symmetrical probability distribution is called a normal distribution. it is also commonly referred to as the normal curve, because the distribution can be plotted by a bell-shaped curve, (see section 2.3.3 on p52-53) 19. The scale along the x-axis of the standard normal distribution indicates____ 1. probabilities 2. the number of standard deviations below and above the mean 3. the p-values 3 Study guide: P52-53 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 21 QUESTION A N S W E R PAGE NR. COMMENTS 20. The mean and standard deviation of a set of test scores are 20 and 8 respectively. What is the z-score corresponding to a test score of 14? 1. 1.33 2. 0.75 3. -0.75 3 Study guide: P55 X - μ Z = σ = 8 = 8 = -0.75 • x represents the variable (test score), • μ is the population mean, • σ the standard deviation of the population from which x was obtained. 21. Suppose the height of military recruits is distributed normally with a mean of 1750 mm and a standard deviation of 50 mm. Drawing repeated samples of 25 recruits each, we expect the standard deviation of the sample means to be about ______ mm 1. 2 2. 10 3. 50 2 Study guide: P61-62, 109 The standard error is an extremely valuable measure because we can use it to estimate how well a sample mean approximates its population mean in general, that is, how much error you can expect on average between the sample mean that you calculated from your sample and the population mean (μ) that you are trying to estimate. In other words, it is an indication of the size of the error that you make by using a sample of a particular size (n) to determine the population mean. This amount of error will decrease as the size of the sample increases. 22. Which of the following formulas give an appropriate way in which the probability of a specific event E can be calculated? 1. Definition (a) only 2. Definition (b) only 3. Both definition (a) and (b) can be used 3 Study guide: P28-31, 46- 50 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 22 QUESTION A N S W E R PAGE NR. COMMENTS 23. What is the principal advantage of transforming measurements z scores? They enable one to ______ 1. determine whether scores are normally distributed around the mean 2. compare a person's scores on tests with different means and standard deviations 3. determine frequency distributions for tests with different means 2 Study guide: P53 This curve has a mean of μ = 0 and a standard deviation of σ = 1and is known as the standard normal distribution, and is by convention indicated with the letter 'z' (so it is also referred to as the zdistribution). The measures on this distribution is referred to as standard scores or z-scores. FIGURE 2.7: The standard normal distribution • In every normal distribution with mean μ and standard deviation σ, approximately 68% of the data falls within one standard deviation of the mean. • Approximately 95% of the data falls within two standard deviations of the mean. • And finally, approximately 99.7% (almost everything) of the data falls within three standard deviations of the mean. • According to the standard normal distribution table (z-table), if z=1then the mean to z = 0.3413. Multiply by 2 to get both sides of the mean = 0.6826 or 68.26% 24. Consider the following Table which represents the mark of a student (X) on each of three subjects and the class averages for those subjects. Subject Student X Mean of class Standard deviation of class History Geography Mathematics 50% 62% 60% 40% 62% 50% 5% 5% 10% In which subject did Student X do best, relative to his class? 1. History 2. Geography 3. Mathematics 1 Study guide: P55-60 Use explanation in study guide from section 2.3.4 The marks should first be converted to z-values, to make it possible to compare them across the different means and standard deviations: _ _ Z = X – X or Z= (X - X) / S S History = (50 - 40) / 5 = 10/5 = 2 Geography = (62 - 62) / 5 = 5/5 = 1 Mathematics = (60 - 50) / 5 = 10/10 = 1 So, it is clear that in the case of subject A, the student’s marks are 2 standard deviations above the mean. In the other subjects the student’s marks are 1 standard deviation or less above the mean. S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 23 QUESTION A N S W E R PAGE NR. COMMENTS 25. Study the histogram below of the exam marks of a group of students in the same class. Note that the values on the horizontal axis are the class (category) limits Assume we use this histogram as a basis for making probability predictions. What is the probability that a student's score will be between 40 and 60? 1. 0.20 2. 0.10 3. 0.30 2 Study guide: P29, 40,47 130-132 142-144 Possible outcomes = 10 + 20 + 40 + 10 + 20 = 100 Favourable events = score > 40 and < 60 = Exam mark of 50 with frequency = 10 = 10 P(score > 40) = Number of favourable events / Number of possible outcomes = 10 / 100 = 0.10 OR Possible outcomes = 10 + 20 + 40 + 10 + 20 = 100 Favourable events = score > 40 = Exam mark 50,freq 10 and exam mark 60, frequency 20 = 10 + 20 = 30 P(score > 40) = Number of favourable events / Number of possible outcomes = (10 + 20) / 100 = 30 /100 = 0.30 Use the scenario below to answer Questions 26 to 31 A researcher suspects that the addition of certain food supplements to the diet of elderly people will reduce the decline in cognitive functioning that comes about because of aging. She decides to test this using a neuropsychological test that measures the speeds with which objects are identified (the Neuropsychological Perceptual Speed or NPS test). The test is standardised in such a way that a higher score implies a better rate of object recognition. it is known that the distribution of scores on this test is approximately normal and that a mean of μ =80 and σ = 20 was found in the population of persons older than 65. To investigate her hypothesis, she obtains a random sample of n=100 persons older than 65. Each member of this sample is given a daily dose of supplements over a period of six months. At the end of this time, each person is tested on the NPS test and a mean of ẋ = 86 is found. The researcher plans to test the hypothesis at α = 0.05. 26. The appropriate research hypothesis suggested by the scenario above is as follows 1. Cognitive functioning declines with age 2. The cognitive functioning of elderly persons is related to their perceptual speed 3. Rate of object recognition will be better for elderly persons who take the dietary supplement than for those who do not 3 Study guide: P15, 71 A psychological hypothesis formulates a testable empirical claim (something that can in principle be observed), and this usually involves postulating a relationship between two or more variables S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 24 QUESTION A N S W E R PAGE NR. COMMENTS 27. The appropriate alternative hypothesis to be tested is______ 1. H1: μ ˂ 80 2. H1: μ ˂ 84 3. H1: μ ≠ 80 1 Study guide: P77, 75, 81-82 28. The mean of the sampling distribution of the mean is ______ 1. 80 2. 86 3. 20 1 Study guide: P60-61 The sampling distribution of means refers to the distribution of the means of all possible samples of a particular size randomly selected from the same population 29. The standard error is ______ 1. 20 2. 2 3. 0.05 2 Study guide: P60- 61, 103-104 We can estimate the size of the error we would make if we used the sample mean as an estimate of the population mean. This is referred to as the standard error, and it is specified in the central limit theorem. The standard error is denoted by σẋ. The σ indicates that we are describing a population, and the subscript ẋ informs us that we are dealing with a population of sample means. The standard error is given by dividing the population standard deviation by the square root of the sample size σẋ = σ / √n if σ = 20 and n = 100, then σẋ = 20 / √100 = 20 / 10 = 2 30. With the information as given in the scenario, what would be the appropriate statistical test to test hypothesis? 1. A one sample z-test 2. A two sample t-test 3. A test of correlation r for relationship between variables 1 Study guide: P100-106 The t-distribution is a statistical distribution with a probability distribution that can be determined, which means that we can use it to predict the chances of obtaining specific outcomes when testing for comparisons of means when the population standard deviation σ is unknown. So, we have to use the t-test (tx) when the population standard deviation (σ) is considered to be unknown - because the given standard deviation comes from the sample. When the population standard deviation (σ) is known we use the z-test (zx) S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 25 QUESTION A N S W E R PAGE NR. COMMENTS 31. The appropriate test statistic is calculated and, based on this number, a computer program is used to determine that the one-sided p-value =0.022. What conclusion can be drawn? The null hypothesis ___ which implies that the supplement ___ cognitive functioning 1. can be rejected, improves 2. can be rejected, does not improve 3. cannot be rejected, does not improve 1 Study guide: P81 A test statistic is calculated to determine how far the observed measurements deviate from what we may expect by chance. Calculating the test statistic is the first step in a process of comparing the observed data with what may be expected by chance (1.e., if the null hypothesis were true). 32. When applying a statistical test, the probability of a type I error is equal to ______ 1. the p-value of the test statistic under the alternative hypothesis 2. the level of significance 3. the p-value of the test statistic under the null hypothesis 2 Study guide: P82-86, An error of Type I is the error we make if we reject the null hypothesis when we should not have done so, and the level of significance represents the greatest risk of doing this that we are willing to take. We know that the extent of the type I error that a researcher is willing to make is controlled by the researcher by setting the level of significance (α) in advance. The probability of a type II error (β) is not controlled in advance by the researcher except for the fact that we know that the lower (smaller) the probability of a type I error (α) the greater (larger) the probability of a type II error (β). 33. A statistical hypothesis is a formal statement about ______ 1. population parameters 2. sample statistics 3. test statistics 1 Study guide: P74 Take note that a research hypothesis always translates into two mutually exclusive hypotheses (1.e. both cannot be true at the same time): a null and an alternative hypothesis. Also remember that, in Topic 1, we referred to quantities such as parameters (population parameters). These particular statistical hypotheses are, thus, statements about the value of a particular population parameter. 34. The sampling distribution of a statistic (e g of the sample mean) can be calculated if we assume that the ____ hypothesis is true, but not if we assume that the ____ hypothesis is true 1. alternative, null 2. null, alternative 3. research, statistical 2 Study guide: P58, 77-79 S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 26 QUESTION A N S W E R PAGE NR. COMMENTS 35. When a statistical test yields a large p-value, which of the following statements is most likely to be correct? 1. The alternative hypothesis is probably true 2. The null hypothesis is probably false 3. The null hypothesis is probably true 3 Study guide: P81 Here is a summary of the important points regarding the p-value: The p-value gives the probability of obtaining the sample result under H0. if the p-value is very small, the probability is very small that the sample result would occur under H0, and one should consider rejecting H0 in favor of H1. The smaller the p-value, the more likely that the null hypothesis is false and should be rejected in favor of the alternative hypothesis. So, if the p-value is very large, the probability is very big that the sample result would occur under H0, and one should consider accepting H0 in favor of H1. The null hypothesis is then probably true 36. The hypothesis "H1μ < 50" is a ____ hypothesis and requires a ____ statistical test 1. non-directional, two-tailed 2. directional, two-tailed 3. directional, one-tailed 3 Study guide: P75-76 The alternative hypothesis can contain any of the symbols '>', '<' or '≠' respectively, the symbols for 'larger than', 'smaller than' or 'not equal to'. When a comparison is between a value that is greater (more) than another, we use the symbol '>' and when a comparison is between a value that is smaller (less than) than another, we use '<'. The statistical test that must be performed in either of these cases is a directional or one-tailed statistical test (we use these expressions interchangeably). When we do not specify what the direction of the difference should be, and both a larger and a smaller difference between means are considered as relevant, the symbol '≠' must be used. The statistical test to be performed will now be a non-directional or two-tailed test. 37. When applying a z-test to compare a sample mean to a known population mean, the p-value represents the probability of ______ 1. rejecting the null hypothesis if it is false 2. obtaining the mean found in the sample of data under the alternative hypothesis 3. obtaining the mean found in the sample of data under the null hypothesis 3 Tutorial 201 The observed results are the values which you find in your sample(s) of data, for example the sample mean and sample standard deviation, or (if it is relevant), the correlation coefficient which you calculated. The p-value shows you the probability of seeing some relationship among these variables based on your calculations (such as a difference between means or a high correlation), if in fact this observed relationship is merely the consequence of chance (in other words, if the null hypothesis was true). You are in fact comparing the observed relationships in the data with what you would expect if the null hypothesis is true by calculating a relevant test statistic. This test statistic can then be used to find the pvalue if we know the probability distribution of the test statistic. if this probability is small, it implies the null hypothesis is probably not true. S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 27 QUESTION A N S W E R PAGE NR. COMMENTS 38. When applying a statistical test, a decision is reached by comparing the_____ to the ______ 1. p-value, level of significance 2. p-value, test statistic 3. test statistic, level of significance 1 Study guide: P82-86 39. The lower we set the level of significance, the greater the probability of - - 1. rejecting the null hypothesis 2. a type II error 3. a type l error 2 Study guide: P82-86 40. For a measurement (x) from a population with µ = 80 and o = 10, calculate the z-score corresponding to x = 95 1. 0 25 2. 0 75 3. 1.50 3 Study guide: P53-56, 162 41. Given that a population with µ = 80 and o = 10 follows a normal distribution, determine p (x :2 95) (Hint: use the result of the previous question and select the closest option below). 1. 0 0668 2. 0 4332 3 0.9332 1 Study guide: P53-56, 162 Refer to Appendix D, Look for 1.50 as per previous question on the standard normal distribution list. Now you have standardised the normal distribution, so the mean is 0 and the std dev is 1. When you look up the z-score (1.5) in the standard normal distribution tables (Appendix D) you will see the larger and smaller portion values. 42. When doing statistical testing, the size of the level of significance depends on 1. a choice made by the researcher 2. the calculation of a test statistic 3. the p-value under H0 1 Study guide: P84-85 The researcher chooses the greatest risk of making an error of Type I (rejecting the null hypothesis in error) that she is willing to make and compares the p-value with this to see whether this p-value is lower than this chosen level of significance (α). While there are conventional values for α such as 0.01 or 0.05, the researcher can in fact use any value he/she deems appropriate. Refer to section 3.3.2 in study guide S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 28 QUESTION A N S W E R PAGE NR. COMMENTS 43. What does it mean to say “the difference between the means of groups A and B is statistically significant? 1. it is unlikely that the alternative hypothesis will be true 2. The sample result is more probable under the alternative hypothesis 3. The null hypothesis explains the sample result 2 Study guide: P85 A statistically significant result implies that the null hypothesis can be rejected. Given the results calculated from the sample it is probable that the alternative hypothesis is correct. The other options all imply that the result was not statistically significant and consequently that the null hypothesis was not rejected. When we find that p-value < α, we say that we have found a (statistically) significant result, and because of this we can reject H0 in favor of H1. 44. Which symbol is conventionally used to indicate the value of the maximum probability that an error would be made if the null hypothesis is rejected which a particular researcher is willing to allow? 1. α 2. σ 3. p 1 Study guide: P29, 79, 83, 85 α = level of significance β = the error of failing to reject a null hypothesis that is false p = probability σ = standard deviation 45. The power of a statistical test refers to the ______ 1. test's ability to give small p-values if the sample size is large 2. test's ability to detect significant results or the accuracy of the test 3. probability that an error of Type I will not be made when the test is used 2 Study guide: P85-86 The ability of a statistical test to detect a significant relationship between variables when such a relationship does in fact exist, is referred to as its power. 46. After findings that a significant difference exists between male and female participants on a test which tests level of creativity, a researcher decides to also calculate an effect size, using Cohen's d. This is used to determine 1. whether a significant effect is sufficiently great to be meaningful from a practical point of view 2. the size of the error that would be made if the null hypothesis is rejected 3. the ability of a statistical test to detect a significant relationship between variables 1 Study guide: P86-87 One way that statisticians have suggested to deal with this problem is by the notion of effect size. Different procedures exist to determine the effect size of a result. In the case of a comparison between means, one way of calculating this is by the use of Cohen's d. Cohen’s d test. S - The study-notes marketplace Downloaded by: jesscoburn | Distribution of this document is illegal S - The study-notes marketplace 29 QUESTION A N S W E R PAGE NR. COMMENTS 47. A researcher wants to test the hypothesis that the mean depression score on a depression scale for patients diagnosed with clinical depression is greater than 120. The statistical hypothesis to be tested is H0 μ = 120 H1μ > 120 She uses a random sample of n=64 drawn from the population of diagnosed patients and finds that ẋ = 127 and s = 24 Which of the values below is the closest to the correct value of sẋ? 1. 0.37 2. 3.0 3. 24 2 Study guide: P105 48. Suppose H0 μ = 100 is tested against H1μ > 100 with α=0.05. if the t-statistic is found to be tẋ = 1.20 and the two tailed p-value is 0.06, what decision regarding the statistical hypothesis can be taken? 1. Reject Ho and accept H1 2. Reject H1and accept Ho 3. Do not reject Ho, and accept H1 3 Study guide: P75 H0: m = 100 H1: m > 100 Here, He specifies that only sample means greater than 100 will be considered as possible evidence