Multivariable linear regression for data with multiple time points
I'm measuring the garbage output of various cities in my country. I have five independent variables as predictors measured at 4-time points (same for the outcome).I'm not interested in the effects of time. I want to know the regression coefficients for each of my variables. To find that out, I could do four separate multiple regressions, one for each time point. But that wouldn't summarize the dat...