A researcher uses a repeated-measures design to compare individuals' performance before treatment with their performance after treatment.If all of the participants show improved performance of 8 or 9 points after treatment,then the researcher should find ____.
A)a sample mean difference near zero
B)a t statistic near zero
C)the variance of the difference scores is near zero
D)a very large variance in the difference scores

Question

A researcher uses a repeated-measures design to compare individuals' performance before treatment with their performance after treatment.If all of the participants show improved performance of 8 or 9 points after treatment,then the researcher should find ____.​
A)​a sample mean difference near zero
B)​a t statistic near zero
C)​the variance of the difference scores is near zero
D)​a very large variance in the difference scores

Quizplus · Accepted Answer

The variance of the difference scores is near zero because all participants show a consistent improvement (either 8 or 9 points), indicating very little variability in how much each participant improved.

A Researcher Uses a Repeated-Measures Design to Compare Individuals' Performance