| A | B |
|---|
| voluntary response sample | comprised of individuals who respond to a general appeal |
| confounding | the effects on a response variable of two or more explanatory variables cannot be distinguished from one another |
| convenience sample | comprised of the individuals easiest to reach |
| bias | systematically favoring certain outcomes |
| simple random sample (SRS) | each individual and every possible sample have an equal chance of being chosen |
| stratified random sample | separate SRS is chosen for each predetermined group |
| multistage sample design | choose a sample in stages |
| sampling frame | the list of idividuals from which a sample is selected |
| undercoverage | groups in the population are left out of the sample selection process |
| nonresponse | individual chosen for the sample can't be contacted or refuses to cooperate |
| response bias | the influence of the behavior of the respondent or the interviewer |
| wording effects | bias resulting from confusing or leading questions |
| systematic random sampling | efficent way to select a sample by thinking of entire list as a set of lists |
| observational study | observes and measures variables of interest |
| experiment | imposes some treatment on individuals in order to observe their responses |
| experimental units | individuals on which the experiment is done |
| subjects | human experimental units |
| treatment | specific experimental condition applied to the units |
| factors | explanatory variables in an experiment |
| level | specific value of a factor |
| placebo effect | response to a dummy treatment |
| control group | group of patients receiving a sham treatment |
| control | a principle of experimental design used to guard against the effects of a lurking variable |
| randomization | a principle of experimental design that uses chance to assign individuals to different treatment groups |
| completely randomized design | all units are allocated at random among all the treatment groups |
| replication | a principle of experimental design used to reduce chance variation in results by using many subjects in the experiment |
| statistically significant | an observed effect too large to attribute plausibly to chance |
| double-blind experiment | neither the subjects nor people in contact with them know which treatment a subject received |
| blocking | used to control the effects of possible lurking variables by dividing units similar in some way prior to assigning treatments |
| matched pairs | blocking consisting of two units each assigned one of two treatments |
| simulation | imitation of chance behavior based on a model that accurately reflects the experiment under consideration |
