[open] JASP: Standard Error in Post-hoc comparisons Repeated Measures ANOVA
JASP version 0.7.5 Beta 2 running on a Macbook Air
Type of analysis: 2 x 3 repeated measures ANOVA with Post-Hoc comparisons
General comment: This week I've finally started using JASP and I really like it. It makes it much easier to do Bayesian analyses.
This question is related to a standard repeated measures ANOVA in JASP though. I wanted to do the following analysis:
A 2 (Distance: Near, Far) x 3 (Target Modality: A, V, AV) repeated measures ANOVA with Response Time as dependent variable.
There was a significant main effect of Distance, a main effect of Target Modality, and an interaction effect.
Next, I wanted to know whether the levels of Target Modality differed using Post-Hoc comparisons. So I did a Post-Hoc test with just a few clicks.
The confusing part was that the Standard Error of the difference between the levels of Target Modality was exactly the same for all comparisons (A vs. V, A vs. AV, and V vs. AV). I started doubting my self so I did the same analysis in SPSS. There the SE is different for each comparison, resulting in a different outcome of the comparisons. Given that I used the latest Beta version of JASP I wondered whether there is a misunderstanding on my part about calculation of SE of the difference or whether something else is going on in the JASP Beta that isn't supposed to happen.
Table of results in JASP and SPSS: