Hallo! I am new to the group and not very experienced in statistics. I thought I had a classical design, two groups with either treatment A or B, measuring the response at 4 time point where the first one is a baseline measurement. I was very astonished not finding any example for this design.
My first idea of analysing was to calculate 3 t-tests with the difference to baseline. But as I found (e.g. Altmann) this is not recommended. He suggested a summary statistic - but this seems not possible because the course in time may vary a lot. My next idea was to calculate a model. But I have different questions there: - Should a random effect be added which has to be nested under treatment? - Better look at the changes from baseline or add baseline as covariate? If taking covariate: *Should the covariate be nested under treatment? *What's about the homogenity assumption? - How can I calculate differences at the three time points between the treatment groups from the model? Or: Is there a typical model for this kind of design? Any help is appreciated. Frank Rigous . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
