Ch 4 extra Review

A random sample is a subset of individuals chosen from a larger set, where each individual has an equal chance of being selected, ensuring that the sample represents the population.

Confounding occurs when two or more variables are associated in such a way that their effects on a response variable cannot be separated, making it difficult to determine the true cause of an effect.

A convenience sample is a non-random sample that is taken from a group of people easy to reach, which may not accurately represent the population.

The purpose of random assignment is to create roughly equivalent groups before treatments are administered, helping to eliminate bias.

Nonresponse bias occurs when individuals selected for a survey do not respond, and their lack of response is related to the topic being studied, potentially skewing results.

Undercoverage bias occurs when some members of the population are inadequately represented in the sample, leading to inaccurate conclusions.

The placebo effect is a phenomenon where participants experience a perceived improvement in condition due to their belief in the treatment, rather than the treatment itself.

A response variable is the outcome that is measured in an experiment to see if it is affected by changes in the explanatory variable.

The wording of survey questions can significantly influence responses, leading to different interpretations and potentially biased results.

A voluntary response sample consists of individuals who choose to participate in a survey, often leading to biased results as those with strong opinions are more likely to respond.