Unit 4 Review: Collecting Data

Describes the fact that some subjects in an experiment will respond favorably to any treatment, even an inactive one.

• bias

• control group

• placebo effect

• random assignment

Occurs when some members of the population are less likely to be chosen or cannot be chosen in a sample.

• placebo effect

• response bias

• undercoverage

• nonresponse

When two variables are associated in such a way that their effects on a response variable cannot be distinguished from each other.

• double-blind

• confounding

• subjects

• placebo

The object/person to which a treatment is randomly assigned.

• experimental unit

• treatment

• random assignment

• control group

A treatment that has no active ingredient but is otherwise like other treatments.

• random sample

• control group

• single-blind

• placebo

A sample that consists of individuals from the population who are selected using a chance process.

• convenience sample

• placebo

• random assignment

• random sample

The design of a statistical study shows bias if it is very likely to underestimate or very likely to overestimate the value you want to know.

• prejudice

• sample

• bias

• random assignment

Design in which the experimental units are assigned to the treatments (or treatments to the experimental units) completely at random.

• completely randomized design

• random assignment

• confounding

• voluntary response sample

The fact that different random samples of the same size from the same population produce different estimates.

• sampling variability

• bias

• confounding

• placebo effect

Sample that consists of people who choose to be in the sample by responding to a general invitation.

• completely randomized design

• response bias

• voluntary response sample

• convenience sample