Well,

I use SPSS and a small but helpful tool called g-power. We completed our pilot study, it is a longitudinal design with one group only. From baseline to last visit we had 4 encounters with most participants.

The group is normally distributed - I want to know whether there is a significant change (within group) in terms of quality of life score - as a visual analog scale. Looking at my g-power it asks me to calculate the effect size, the options would be using the variance explained by especial effect and variance within groups. Can you tell me what are these variable? The other option would be using the partial n2 . when I ran my repeated measures I asked to have the effect size result and my partial Eta squared with sphericity assumed was .251. Do you work with g-power? can you help me with this?