A SHAZAM User asked:
I am a student at XXX University and am using the Shazam program to create a hedonic pricing model of laptops for a fourth year course.
My problem is that I have used dummy variables to signify the makers of each laptop. When I try to perform the OLS function, I get a message saying "Matrix Inversion failed in row 19". " This usually indicates perfect multicollinearity with variable constant".
I have searched the internet to no avail for an answer. When I run the regression without the dummy variables, the OLS works. How can I perform OLS on my data including the dummy variables? Do I have to specify that they are dummy variables somewhere in the code?