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AP Stats Unit 3 Test
Unit 3 (Chapter 5)
Question | Answer |
---|---|
What is an observational study? | observes individuals and measures variables but does not impose a treatment |
What is an experiment? | imposes a treatment on individuals and observes their response |
What is a population? | group of individuals that we want info about |
What is a sample? | the part of the population that we are examining to gather info |
What is a census? | contacting every individual in a population to gain information |
Voluntary response sample? | consists of people who choose to respond (non random) |
Convenience sampling? | contact individuals easiest to reach (non random) |
What is a simple random sample (SRS)? | gives everyone in each group the same chance of being chosen. Chosen by using random digits table F, label each individual, and read numbers to select them |
What is a stratified random sample? | divide the population into strata (groups by similarity) and select a SRS for each strata. Then combine the selected groups to provide the sample |
What is a multi stage sample? | select naturally occurring groups in a population and choose SRS within each group |
What is a systematic random sample? | order the population, randomly select the starting point, and select every nth item based on your sample size |
What is bias? | systematic errors in the way a sample represents the population |
What is voluntary response bias? | only those with a strong opinion take the time to respond |
What is undercoverage bias? | when the design of the sample leaves out certain parts of the population |
What is nonresponse bias? | people have been contacted but don't respond or people that were select can't be contacted |
What is response bias? | the person responding might lie |
What is question wording bias? | when the question is not clear or written with strong words for/against the topic |
What are experimental units? | the individuals on which the experiment is done |
What is a treatment? | a specific condition being applied to the units (explanatory variable) |
What is a factor? | a level of the treatment |
What is the placebo effect? | when patients respond favorably to a treatment even though they are actually taking the placebo. they are responding to the ides of the treatment not the actual treatment |
What is the control group? | the group of individuals that receive a sham treatment which enables the researcher to control the effects of lurking variables and the placebo effect |
What are the principles of experimental design? | control, randomize, replicate, and block design |
What is a completely randomized design? | when all experimental units are allocated at random |
What is a double blind experiment? | the researcher and the experimental units know what treatment they are recieving |
What is a matched pairs design? | 2 identical groups based on characteristics of individuals or 1 group gets both treatments (randomly decide which group gets which treatment) |
What is a block design? | when you group the experimental units based on a lurking variable before conducting the experiment then give a treatment to the blocks |
What is a confounding variable? | those that affect other variables in a way that produces spurious or distorted associations between two variables. |
What is a lurking variable? | variable that is not included as an explanatory or response variable in the analysis but can affect the interpretation of relationships between variables |
What is a simulation? | imitation of chance behavior, a model that accurately reflects the experiment |
What are the steps to make a simulation? | state (the problem/describe experiment), plan (how will you use chance to imitate the process, tell what you will record), do, conclude (use results to answer question of interest) |