Using summary measures as inputs to compute an ANOVA involving one between and one within subjects factor each with two levels
We can also compute mixed ANOVAs with summary information involving repeated measures and between subject factors but we need more information. In particular if we denote B1 and B2 as the two levels of the between subjects factor, B, and W1 and W2 as the two levels of the within subjects factor, W then we need the means, standard deviations, sample sizes and correlations (r) given in the table below.
|
W1 |
W2 |
r |
B1 |
mean1, sd1, n1 |
mean2, sd2, n2 |
r(mean1,mean2) |
B2 |
mean3, sd3, n3 |
mean4, sd4, n4 |
r(mean1,mean2) |
These can then be inputted into this spreadsheet which will then compute the F ratios for the B and W main effects and the B x W interaction. Note: we cannot use summary inputs to test ANOVA model assumptions.
The spreadsheet computes both type II (recommended) and type III sums of squares (SPSS default) for the main effects which respectively ignore and adjust for the B x W interaction.