TEST BANK FOR PROBABILITY AND STATISTICS UNIT 1 TEST

TEST BANK FOR PROBABILITY AND STATISTICS UNIT 1 TEST Anecdotal evidence - ANSWER-results from situations that come to mind easily and is of little value in scientific research bar graph - ANSWER-a visual display, usually of proportions, which displays the distribution of a categorical variable. Binary variables - ANSWER-categorical variables with only two possible categories, for example, male and female. blind - ANSWER-subjects do not know whether or not they which treatment they were given. Categorical variable - ANSWER-records a group designation such as gender. confounding variables - ANSWER-variables that differ among the explanatory variable groups in such a way that we cannot distinguish their effects from those of the explanatory variable. Prevent us from drawing a cause-and-effect conclusion between the explanatory and response variable. Data - ANSWER-the numbers or categories recorded for the observational units in a study. Distribution of a variable - ANSWER-refers to its pattern of variation. dotplot - ANSWER-useful for displaying the distribution of relatively small datasets of a quantitative variable. double-blind - ANSWER-the person evaluating the subjects is also unaware of which subjects receive which treatment. Experiment - ANSWER-a study in which the experimenter actively imposes the treatment on the subjects. Ideally, the groups of subjects are identical in all respects other than the explanatory variable so that the researcher can then see the explanatory variable's direct effects on the response variable. explanatory variable - ANSWER-the variable whose effect you want to study lurking variables - ANSWER-variables that are not considered in the study but that may also be related to the response variable. observational study - ANSWER-researchers passively observe and record information about observational units. Does not control for the possible effects of confounding variables so it cannot establish a cause-and-effect conclusion. Observational unit - ANSWER-The person or thing to which the number or category is assigned parameter - ANSWER-a number that describes population. placebo effect - ANSWER-subjects often respond positively simply to being given a treatment, whether or not the treatment is actually effective. population of a study - ANSWER-the entire group of people or objects of interest. precision - ANSWER-how much the values vary from sample to sample. Related to sample size: sample statistics from larger samples are more precise and closer together than those from the smaller samples. Quantitative variable - ANSWER-measures a numerical characteristic such as height random assignment - ANSWER-preferred method of assigning subjects to treatments (explanatory variable groups) in an experiment: each subject has an equal chance of being assigned to any of the treatment groups. Randomized comparative experiment - ANSWER-Each subject has an equal chance of being assigned to any of the treatment groups. Research question - ANSWER-looks for patterns in a variable or compares a variable across different groups or looks for a relationship between variables. response variable - ANSWER-the variable that you suspect is affected by the other variable. sample - ANSWER-typically small part of the population from whom or which data are gathered to learn about the population as a whole. sample size - ANSWER-number of observational units (people or objects) studied in a sample. sampling bias - ANSWER-if a sampling procedure tends to systematically over-represent certain segments of the population and to under-represent others. sampling variability - ANSWER-the fact that the values of sample statistics vary from sample to sample. simple random sampling - ANSWER-every member of the population has the same and equal chance of being the sample ultimately selected. statistic - ANSWER-number that describes a sample. treatment - ANSWER-explanatory variable group unbiased - ANSWER-if values of the statistic from different random samples are centered at the actual parameter value. Variability - ANSWER-phenomenon of a variable taking on different values or categories from observational unit to observational unit. Variable - ANSWER-any characteristic of a person or thing that can be assigned a number or a category.