AP Statistics Exam Study Guide Questions With Complete Solutions

How is a population measured? correct answer: a population is measured by a census. How is a sample measured? correct answer: A sample is measured using a sampling technique, of which there are several. Why do we often measure samples instead of populations? correct answer: Collecting data from an entire population is often impossible, infeasible, or beyond the capability of the resources we have available. Samples can supply good estimates of the population, and are much easier to collect data for. Bias correct answer: anything that causes a sample to be not representative of the population of interest. • What is the difference between sampling error and sampling bias? correct answer: Sampling error is an unavoidable phenomenon, because no sample can perfectly represent the population. Sampling bias, however, is a systematic and avoidable failure of the sample to at least be reasonably representative of the population. How can a small sample size affect the validity of the sample? correct answer: Small sample sizes will result in high sampling error, thus reducing the usefulness and applicability of the data. Undercoverage correct answer: When one or more sub-groups within a population are not adequately represented within the sample. This is particularly important if there is a meaningful difference between which groups are represented and which aren't, with regard to the research question. Nonresponse bias correct answer: When the attempt is made to include all relevant sub-groups, but some groups fail to respond or provide meaningful data. Again, particularly important if there is a meaningful difference between which groups are providing responses and which aren't. Voluntary response bias correct answer: When subjects are allowed to choose whether or not they are in the sample. This tends to cause subjects with strong opinions to be overrepresented in the sample. Loaded questions correct answer: When a question is designed in such a way to elicit a certain response, rather than seeking to gather accurate information. False answers correct answer: When the wording or nature of a question is such that subjects are unwilling or unable to answer truthfully, and thus provide inaccurate or estim