Hello, I've received some expert help here on a couple previous occasions
(thanks). I have an issue bothering me, which I'd like to present to you.
I'm doing a two-way, 2X2 ANOVA. Suppose I have 20 subjects, and each has
25 observations of the following types:
drug1-doseA (25 for each subject)
drug1-doseB ( " )
drug2-doseA
drug2-doseB
Each observation consists of the subject's temperature. The objective is
to determine whether there is a main effect of either factor (drug type
and doseage) on temperature, and whether there is an interaction between
the two.
My question is, should I determine an average for each subject in each of
the four cells, and use this as data to put into the ANOVA, or should I
put the raw trials themselves into the ANOVA? There would be 80 datapoints
and 2000 data points respectively, 20 or 500 per cell. I have seen both
approaches taken but never heard a satisfactory justification. It would
seem they are not equivalent since the latter, having more observations,
has greater power. What are the implications of each option?
Thank you much,
Jim
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