Darren is of course correct, but I hope the following, brief,
intentionally non-technical explanation will help:
Repeated measures analyses are needed only when there are three or more
measurements from a given experimental unit and the two or more
measurements are both on the right hand side of th
With respect to calculating the epsilon index of sphericity for ANOVA,
discussed on pp. 45-47 of:
http://www.psych.upenn.edu/~baron/rpsych.pdf
It notes that epsilon is not required for a repeated measures design with
only k=2 levels, as the minimum value of epsilon (e) is given by:
e = 1/(k-1)
