i am currently analysing a dataset of 10,000 transactions. I am analysing the effect of different advertising campaings on the quantity of chairs by using multiple linear regression model with zip code and day dummies. I am interested in formally writing the regression model down and wanted to ask if you think it is okay in the following way:

**Yi = ß0 + ß1 * Ti + ß2 * Xi + ß3 * di + ei**

Yi = quantity of chairs

i = specific transaction

Ti = a set of dummy variables that indicates which add the customer of the transaction saw

Xi = Dummy for the zip code to which the products where shipped

Di = Dummy for the date of the transaction

ei = error term

It would really help to know if it is okay. I have some problems with my output and wanted to start at the basiscs.

Best regards

Renato