Simple effects analyses not so simple!

#1
Need some help as to what way should the simple effects of an age_category (young, old) x condirtion (A, B, C, D, E) interaction be analysied for the research question: "what specific conditions impact reaction time the most for young, and which impair the most for old?" Is it: 1. the simple effects of Age at each level of Condition, or 2. the semple effects of condition for each level of age??? Thanks to anyone who can help me out!:tup:
 
#3
My confusion

I was thinking it was 2 (compare the effect of condit (a,b,c,d,e) for old and ondit (a,b,c,d,e) for young = 2 analyses)
If predicting a difference between old and young,shouldnt i examine the simple effects of phystat on on young and old seperately (ie. phystat at each level of age = is there a diff between a,b,c,d,e, for young and is there a diff between a,b,c,d,e, for old). so for the simple effects i would vary the condition and keep age constant so i can conclude an effect of condition on age. then i'd further examine these 2 simple effects with pairwise comparisons correcting with bonferroni.

the other way around, looking at the simple effects of age at each level of condit (ie. 5 analyses) will only determine if there is a diff between yound and old for A, then young and old for B etc. so i'm not finding what condition is effecting young or old most but just that young and old either differ or not for that condition.

This was just my train of thought so may be wrong. Most people i have spoken to said they are doing age at each level of condition but i can't see how that would provide the relevant info - this is why im confused!:confused:
 

JohnM

TS Contributor
#4
If you compute the effects:

A(old) - A(young)
B(old) - B(young)

and so forth for C, D, and E, you should be able to answer the question:

"what specific conditions impact reaction time the most for young, and which impair the most for old?"