Exam 9: Internal Validity

Participants who scored very high on a test, will tend to score ____ on the retest

In a two-group study, 10 participants drop out of each group before the treatment is administered. This poses the greatest threat to the study's

The most serious problem with arbitrary assignment of participants to groups is:

If something other than the treatment is responsible for the effect, there is a problem with the study's

Regression towards the mean would suggest that a group that was formed based on extremely low scores on a pretest, would have even lower scores on a second testing regardless of the effects of any treatment.

The fact that participants are matched on measures of characteristics rather than on the characteristics themselves makes matching vulnerable to:

Which is a likely threat to validity for BOTH pretest-posttest designs and matched groups designs?

When you increase external validity you will usually also improve internal validity.

In a two-group study, a highly unusual thing happens: None of the no-treatment group subjects drop out, but 90% of the treatment group subjects drop out. The most obvious problem with this study is

Studying only twins might help an investigation's

Why might participants change between pretest and posttest?

Why do the authors say that matching on pretest scores only makes your groups APPEAR to be identical rather than actually making the groups identical?

Which of the following would eliminate selection error?

Regression toward the mean is most serious as a threat to internal validity when

Mary scored 100% on her first biology test but 96% on the second, even though she studied harder for the second test. Which of the following best explains Mary's deteriorating pattern of performance?

Which of the following is the most serious threat for the typical two-group design?

Maturation refers to the effects of outside events, other than the treatment, that might influence participants' scores.

If a test had no random measurement error (was perfectly reliable), which of the following would not be a threat?

The degree to which the results of a study can be generalized to other populations is called external validity.

If participants in a two-group study are matched on only a few of the relevant characteristics, which of the following is the most serious threat to the study's internal validity?