Hi everyone,
I have a question regarding linear mixed model with repeated measurement. I have one dependent variable (about Body image) and two independent variable: 1)Group (Physical activity, amateur sport group, sedentary group, elite sport group), 2) TIME (PRE and POST). So, regarding time, I have two time point. I would ask if it possible to do a linear mixed model without to indicate the repeated measurement, but only including the intercept on subject in the random effect. Bacause if I include also repeated measurements, the output tell me that matrix is not positive. I don't know if the problem is that i have only two time point