# Mixed model, repeated measures, manova, nested? nominal

#### Joan.m

##### New Member
Hi.

I am not sure how to approach the statistical analysis of the following study. Any insights would be greatly appreciated. Thanks!

So, I have two independent groups, group A and group B. I am collecting data for 3 different tasks (Task 1, Task 2, Task 3) at 3 different time points, Pre, During and Post. There are 3 trials for each of the tasks, so I have 9 observations per subject per task (3 pre, 3 during and 3 post per task), 27 observations in total per subject. The problem is that the dependent variable, which is Pattern P, is nominal (each pattern coded with numbers from 0-5).

Group A

Task 1: Pre1, Pre2, Pre3, During1, During2, During3, Post1, Post2, Post3

Task2: Pre1, Pre2, Pre3, During1, During2, During3, Post1, Post2, Post3

Task 3: Pre1, Pre2, Pre3, During1, During2, During3, Post1, Post2, Post3

Group B

Task 1: Pre1, Pre2, Pre3, During1, During2, During3, Post1, Post2, Post3

Task2: Pre1, Pre2, Pre3, During1, During2, During3, Post1, Post2, Post3

Task 3: Pre1, Pre2, Pre3, During1, During2, During3, Post1, Post2, Post3

I am interested in pattern differences between the 3 time conditions, between the 3 different tasks and between the 2 groups. I would normally do a repeated measures MANOVA in this case, with 2 factors (Task with 3 levels and Time with 3 levels) Within-Subjects and SubjectGroup as a Between-Subjects factor, but in this case I have 3 observations and not 1. Since the measure is nominal, I can't take the mean of the 3 trials. Perhaps, treating each trial as nested would solve the problem? If yes, can I do this with repeated measures in SPSS? Or another type of analysis would be preferable? Any suggestions?

Many thanks!