I'm attempting to extract t-values from a series of published papers for a meta-analysis. The specific measure of interest is the difference in performance (proportion correct on a memory test) between a Treatment Group and Control Group.
Some papers report the results of a t-test between the Treatment and Control groups--exactly what I need. Others however, do not.
Instead, those papers only provide Means, SDs, and n. When the experiment is between subjects, that is sufficient for me to calculate the t-statistic.
However, when the experiment involves a within-subjects design--although I have Means, SDs, and n for the Treatment and Control conditions, I do not have the SD of the difference scores for each subject (Treatment minus Control).
Is there a way that I can estimate what the results of a t-test would be in that case?
Further detail: in some of these within-subjects studies, each subject went through a Treatment, Control, and an Alternate Treatment condition. An ANOVA reporting a main effect of condition (3 levels) is reported.
Thanks in advance for any assistance!