Please help! Should i use a Mixed ANOVA?

#1
I am struggling on which type of ANOVA to use for my work, I will provide as many details below about the study design, at the moment I am thinking mixed ANOVA but im encountering some problems which suggest that I have chosen the wrong type.

I have two groups, one with a particular defect and one without, both hold 40 participants. Each group had to take part in three tests, each relating to a particular intellect, i.e. logical ability. Each participant completed the same tests and therefore each participant had three different scores to their name. The aim is to determine whether the defects led to cognitive functioning problems, as determined by the three test scores.

Since there was an independent sample (two separate groups), but they all took part in the same three tests, would this be a mixed design? Or should I perhaps be using a two way ANOVA? I am so confused, any help with be so helpful.
 

bugman

Super Moderator
#2
If the responses are not correlated then it may be appropriate to perform three separate ANOVAs - one for each test. If there is some correlation, then a MANOVA might be more appropriate.

Because your participants are not the key area of interest, I would include "participant" as a random variable.
 

Miner

TS Contributor
#3
To clarify: A mixed design means that at least one factor's treatments were applied to different groups (i.e., Between-groups) while at least one more factor's treatments were applied to the same groups (i.e., Within-subjects, or repeated measures). In your example, you have only one factor (with two treatment levels) and three responses. As bugman stated, you could do separate ANOVAs on each response or a MANOVA on all three. You could also perform separate t-tests on each response, since you only have two treatment levels.