I'm currently having trouble defining what type of ANOVA I need to run as well as how to run it correctly. This is the following setup:

I have 4 groups of 30 people doing a 2-session task (one after the other), where I record response time. In each of the 4 groups the sessions they do have 2 conditions:

  • AB
  • BA
  • AA
  • BB

My goal is find effects for condition: A or B, as well as ordering effects 1st or second session to explain the shift in means for the response time $Z$. I am currently having trouble on how to correctly run an ANOVA for this problem. My current solution (that I think is incorrect) is to do the following:

To construct a table where I have response time $Z$ in the main column, and for the groups have 2 variables: condition $(0,1)$ for A or B respectively, and session id $(0,1)$ for 1st and 2nd session respectively. It would look something like this:

$Z_{AB}^1$ : 0 0

$Z_{AB}^2$ : 1 1

$Z_{BA}^1$ : 1 0

$Z_{BA}^2$ : 0 1

$Z_{AA}^1$ : 0 0

$Z_{AA}^2$ : 0 1

$Z_{BB}^1$ : 1 0

$Z_{BB}^2$ : 1 1

Sure, I can run this through MATLAB's anovan, and I get a result, but a closer look reveals the problem I think I am doing in my analysis: I am pooling together the results from $Z_{BB}^2$ and $Z_{AB}^2$, as if the second session of both of these groups is independent of the first (which may not be the case -- as they did in fact have different preceding conditions). On the flipside, pooling together the $Z$'s from $Z_{AB}^1$ and $Z_{AA}^1$, should not be a problem as they are both the first session of the within subject experiment. So I am confused: Is this still a correct approach, or under what conditions is my proposed analysis correct/incorrect? Am I being more rigorous by finding a significant result by assuming independence?

  • $\begingroup$ Could you be able to fit general linear model? $\endgroup$ – user158565 Nov 13 '18 at 23:38

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Browse other questions tagged or ask your own question.