Would it please be possible to help me with a statistics query. I have asked for the partial eta squared on the output of a one-way within subjects ANOVA from SPSS and it has given me the value .137. According to Cohen (1992) the classifications for effect sizes should be; r=.10 small, r=.30 medium and r=.50 large (I am unsure whether these classifications can be attributed to partial eta squared?)
I appreciate this is a basic question but please may I clarify my value falls in the small effect category? Additionally, does this suggest that the proportion of variance explained by the IV on the DV and not explained by other variables in the analysis is 13.7%?
Any help would be greatly appreciated!! Thank you!