Which of the following poses a serious problem when using a t test for dependent means, one-tailed?
A)The population of difference scores is even moderately different from normal.
B)The sample has less than 40 participants.
C)There is a ceiling effect in the test, which is likely to make the population of difference scores highly skewed.
D)Pretest and posttest scores are highly correlated with each other.

Question

Quizplus · Accepted Answer

A ceiling effect can create a highly skewed distribution of difference scores, which violates the assumption of normality necessary for the t test. This can result in inaccurate or misleading results. The other options, such moderately deviating from normality or having a small sample size, may affect the power of the test but are not necessarily serious problems. Having highly correlated scores may actually improve the precision of the test.

Which of the Following Poses a Serious Problem When Using