A repeatedmeasures study has n 8 participants and k 3 trea

A repeated-measures study has n = 8 participants and k = 3 treatments. For this study, dferror= 21.

True or False? Please explain

Solution

False.

Number of treatments = 3

Let the number of levels in the 3 treatments be a, b and c respectively.

Df error = abc(n-1) = abc(8-1) = 7abc where a>1, b>1 and c>1

As we can see, df cannot be 21 as \'abc\' can never equal 3, as minimum value a,b and c can take is 2. (Number of levels cannot be 1 as an effect of treatment is compared across multiple levels)