Question

A researcher uses a repeated-measures design to compare individuals’ performance before treatment with their performance after treatment. If all the participants show improved performance of 8 or 9 points after treatment, what should the researcher find _______
a) a sample mean difference near zero.
b) the statistic near zero.
c) the variance of the difference scores is near zero.
d) none of the other options is correct.

Answer 1

Answer:

c. the variance of the difference scores is near zero

Step-by-step explanation:

If all the participants show improved performance of 8 or 9 points after treatment, what should the researcher find  - the variance of the difference scores is near zero.

But this can be true only when the original scores had a low variance.