Products and Polynomials Stata Class Notes Products and Polynomials Product Variables Product variables are created by multiplying one variable times another and using the product as a variable in a regression analysis.
Some researchers think that all product variables are interactions.
Whether you believe that all product variables are interactions or not, it is the case that all interations can be concieved of as product variables. We will useing the hsb2 dataset to illustrate product variables. Note that the regression coefficients for read and female are significant while the coefficient for the fbyr product variable is not. One way of interpreting the product variable is to think of it as examining the the difference in the regression slopes for, in this instance, males and females. Since the product variable is not statistically significant, the diffenence in the regression coefficients for males would not be significantly different from the coefficient for females.