For a repeatedmeasures study comparing two treatments with a
For a repeated-measures study comparing two treatments with a sample of n = 9 participants, the difference scores have a mean of MD = 4.90 with SS = 72. What is the estimated standard error for the sample mean difference?
Solution
Mean difference = 4.9
Therefore,
Sum of differences, sum(D) = 4.9*9 = 44.1
 
 Standard Error = sqrt([sum(D²) - sum(D)²/n]/n(n-1))
 
 sqrt((72 - (44.1²/9))/(9*8))
 = 1.41 Answer

