Aresearcher 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.

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.

answer: a.

step-by-step explanation: the answer is a. because, you need to converge the fractions to find a solution.

1) 2/5

2) zero=0/1

3) zero=0/2

4) -4/5

5) undefined=3/0