can you use one model for production but both can fixed effects be applied to cross section model what is the difference between cross section and fixed effects can a revenue model use cross section and a time dummy which model is used cross section how to use cross section and fixed effects model can you use cross section model and time model cross section model for revenue can you have dummies in both cs and time what model has dummies for production cross section and fixed effects cross section and fixed effect model which variable should you use for cross-sectional and fixed effects models? which model is cross section model can you use cross-section and fixed effects model is cs in revenue is cross section and time fixed is cross section and time the same which model uses cross section and fixed effects which model uses cross section or time in the same way?