A repeated-measures study comparing two treatments with n = 4 participants produces MD = 2 and SS = ...

A repeated-measures study comparing two treatments with n = 4 participants produces MD = 2 and SS = 75 for the difference scores. What is the estimated standard error for the sample mean difference?
 
  a. 25 c. 5
  b. 25/4 = 6.25 d. 2.5

Question 2

The null hypothesis for a repeated-measures test states:
 
  a. each individual will have a difference score of D = 0.
  b. the overall sample will have a mean difference of MD = 0.
  c. the entire population will have a mean difference of D = 0.
  d. All of the other options are correct.

Question 3

For a repeated-measures study, if the null hypothesis is true, then what value should be obtained for the sample mean?
 
  a. MD = 0 c. MD< 0
  b. MD> 0 d. MD near 0

Question 4

If the null hypothesis is true, what value is expected on average for the repeated-measures t statistic?
 
  a. t= 0 c. t= 1.96
  b. t= 1 d. t> 1.96