# Interaction terms in linear models

Basic question: does lm(y~x_1*x_2) correspond to y_i = \beta_0 + \beta_1x_{1,i} + \beta_2x_{2,i}+\beta_3x_{1,i}x_{2,i} or just y_i = \beta_0 +\beta_1x_{1,i}x_{2,i}?

The * represents crossing, I.e. your first interpretation. For the other replace with colon :

Thanks, that's great.

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.

If you have a query related to it or one of the replies, start a new topic and refer back with a link.