AP Statistics Chapter 4

Simple Random Sample (SRS)

Sample method where every sample of a certain size “n” has the same chance of being selected

Stratified Sample

Sample method where strata have similar characteristics

Cluster Sample

Sample method where clusters have different characteristics that are representative of the population

Systematic Sample

Sample method where random starting point is chosen and then individuals are chosen in regular intervals

Selection Bias

bias that leaves out a significant part of the population when the sample is collected. Can happen with self-selected volunteers

Convenience Sampling

using easily available group to form a sample

Measurement Bias

bias where the method of measurement produces values that are different that are different than true value

Response Bias

bias where observation method is biased in that individuals are asked about illegal behavior or unpopular beliefs

Nonresponse Bias

bias where responses are not obtained from all individuals selected

Extraneous Variables

variables that affect response but are not explanatory variables

Confounding Variables

variables whose effects on the response can’t be distinguished from each other

Randomized Experimental Design

Subjects are randomly assigned a treatment

Randomized Blocks Experimental Design

Subjects are randomly assigned treatment within a block. Blocks have similar characteristics