Consider the following data from a repeated-measures design. You want to use a repeated-measures t test to test the null hypothesis H0: µᴅ= 0 (the null hypothesis states that the mean difference for the general population is zero). The data consist of five observations, each with two measurements, A and B, taken before and after a treatment. Assume the population of the differences in these measurements are normally distributed.
Complete the following table by calculating the differences and the squared differences:

Difference Score Squared Difference Score
Observation A B (D = B-A) (D²)
1 1 2
2 3 3
3 4 6
4 6 5
5 6 8

1) The mean difference score is Mᴅ = .
2) For a repeated-measures t test, you need to calculate the t statistic, which requires you to calculate s and sᴍᴅ.
What is the estimated standard deviation of the difference scores?
What is the estimated standard error of the mean difference scores?
What is the t statistic for the repeated-measures t test to test the null hypothesis H0: µᴅ = 0?