Straighterline Statistics FINAL EXAM PREP 2025/2026 COMPLETE QUESTIONS WITH CORRECT DETAILED ANSWERS || 100% GUARANTEED PASS <BRAND NEW VERSION>

Straighterline Statistics FINAL EXAM PREP 2025/2026 COMPLETE QUESTIONS WITH CORRECT DETAILED ANSWERS || 100% GUARANTEED PASS &lt;BRAND NEW VERSION&gt; 1. Four steps in the process of statistics - ANSWER 1. Producing Data Exploratory Data Analysis Probability Inference 2. Categorical variable - ANSWER places individuals into one of several groups Two types: nominal and ordinal 3. Quantitative Variable - ANSWER represents a measurement or a count Two types: Interval and ratio 4. Nominal Variable - ANSWER categorical variables where there is no natural order among the categories 5. Ordinal variable - ANSWER categorical variables where there is natural order among the categories 6. Interval Variable - ANSWER a measurement or count for which it makes sense to talk about the difference between values, but it does not make sense to talk about the ratio between values; 0 does not represent the absence of quanitity 7. Ratio Variable - ANSWER quantitative variables for which it makes sense to talk about the difference between values AND the ratio between values; 0 represents the absence of quantity 8. Standard Deviation Rule - ANSWER Approximately 68% of observations fall within 1 sd of the mean, 95% within 2 sd, 99.7% (or virtually all) within 3 sds 9. Interquartile Range (IQR) - ANSWER Middle 50% of the data IQR= Q3-Q1 10. Finding an outlier using IQR - ANSWER An observation is considered a suspected outlier if it is: less than Q1 - 1.5(IQR), or more than Q3 + 1.5(IQR). 11. Interpreting scatterplots: 1. positive relationship displays as 2. negative relationship displays as - ANSWER 1. upward slope 3. downward slope 12. Interpreting Scatterplots: How to tell if a linear relationship is strong or weak - ANSWER closer to -1 is a strong negative linear relationship closer to +1 is a strong positive linear relationship close to 0 is a weak linear relationship 13. Interpreting Scatterplots: Linear regression - ANSWER Finding the line that best fits the pattern of the linear relationship (the line that describes how the response variable linearly depends on the explanatory variable 14. Interpreting Scatterplots: Least Squares Regression Line - ANSWER Has the smallest sum of squared vertical deviations of the data points from the line. 15. Interpreting Scatterplots: Extrapolation - ANSWER Prediction for ranges of the explanatory variable that are not in the data; is not reliable and should be avoided 16. Association (does/does not) imply causation. - ANSWER Does not 17. Lurking Variable - ANSWER a variable that is not among the explanatory or response variables in a study, but could substantially affect your interpretation of the relationship among those variables 18. Simpson's paradox - ANSWER When a lurking variable causes you to rethink the direction of an association 19. Probability sampling plan - ANSWER any sampling plan that relies on random selection (avoids bias). 20. Simple Random Sampling - ANSWER Every member of the population has an equal probability of being selected for the sample 21. Cluster Sampling - ANSWER Used when the population is naturally divided into groups. Take a random sample of clusters and use all individuals within those clusters as the sample. 22. Stratified sampling - ANSWER Used when the population is naturally divided into sub-populations called stratum. Choose a simple random sample from each stratum and use these together as the sample. 23. Multistage sampling - ANSWER a probability sampling technique involving at least two stages: a random sample of clusters followed by a random sample of people within the selected clusters 24. Observational study - ANSWER values of the variable or variables of interest are recorded as they naturally occur; no interference 25. Sample surveys - ANSWER a particular type of observational study in which individuals report variables' values themselves, frequently by giving their opinions. 26. The main score on a college entrance exam is 1200, and the standard deviation is 100. If the scores are normally distributed, what is the likelihood of the score greater than 1450? - ANSWER 0.0062 27. What type of distribution is depicted in the graph? - ANSWER Normal 28. A school gives an exam for which the scores are normally distributed. What proportion of students score within 2.3 standard deviations of the mean? - ANSWER 0.98 29. The mean score for 18 holes of golf on the parkvale municipal course is 68, with a standard deviation of 12. Low score is 95. What is Z - score does this correspond to? - ANSWER 2.25 30. Damien determines that the difference is he found in his study are statistically significant at the 0.05 level of significance. What is the correct interpretation of the finding? - ANSWER 95% of the study participants achieve the level of performance expected 31. The central limit theorem says that if the sample size doubles, the sampling distribution of the sample mean will - ANSWER Approach a normal distribution 32. Scores on a certain standard achievement test are normally distributed with mean μ = 100 and standard deviation σ= 10. If you take multiple samples of size 16, what percent of sample of means will be between 95 and 105. - ANSWER 95.4% 33. A student performed a chi square test with 5° of freedom. What would be the critical value of the chi square statistic, assuming a significance level of P&lt; 0.05 - ANSWER 11.07 34. Withdrawn from a normal distribution, 95% of the sample means will fall within how many standard deviations of the population - ANSWER 1.96 35. A maple syrup manufacturer asked 100 customers to rate its brand of maple syrup on a scale of one to 10. The mean rating was seven, with a sample standard deviation of 1.5. Based on this sample, what is the 95% confidence interval for the estimate of the population mean? - ANSWER (6.7, 7.3) 36. A regression analysis suggest that the number of children and employee has predicts the number of personal days he/she will take off work. The life of the regression line is 3.2 and the lower bound of the confidence interval for this slope is 0.8. What is the upper bound? - ANSWER 5.6 37. A coach was just to determine whether her basketball team is performing worse this year than in previous years. The coach knows that over the past several years games, the team scored an average of 84 points in the last year, with 36 games, they scored an average of only 71 points, with a standard deviation of 24 points. What T test statistic does this score correspond to? - ANSWER -3.25 38. In a statistical analysis, how does the T distribution differ from the z distribution? - ANSWER It depends on sample size 39. In hypothesis testing, a type one error occurs when - ANSWER A chance result is reported as statistically significant 40. An analyst predicts that clients who use a certain investment strategy will have below average profits. With a sample of 21 clients, the analyst performs a one tailed T test of this hypothesis at the 95% confidence level, resulting in a statistic of -1.65. How should the analyst interpret the result? - ANSWER The null hypothesis is not rejected 41. A researcher test the hypothesis that math scores are significantly different between two groups of students. The test yields a p value of 0.01. What is the correct interpretation of this value? - ANSWER The two score distributions have common values one percent of the time 42. A class of 25 students took a reading test before, and after completing an intensive vocabulary course to determine whether there was a change in scores in either direction. The mean pretest score was 24, and the mean post test score was 32. The standard deviation of the difference was nine. What value of the T statistic does this difference correspond to? - ANSWER 4.4