I have two groups of ten observations each, where the weight are measured at three different points in time. Let´s say baseline, 2 months and 5 months after baseline.
Now I would like to draw a conclusion if the mean of one group is lower than the other group over time. They most likely weigh the same at the first measurement, with little variation.
There´s been a suggestion to fit a simple linear regression, where we use the difference in mean of the two groups as response and time as dependent. In my opinion it seems wrong, we will only have three observations. Would it be more correct to fit som kind of Repeated measurements ANOVA or any other suggestion? Thankful for any input.