2. (21 points) lrnagine that you don't believe that equation (1) is the correct pop- ulation regression model. Instead you think that the correct population regression model should take into account that the length of a book affects sales by a different amount depending on if the book was originally written in english and if the book is fiction. Estimate this regression using OLS and interpret all the estimates. You can assume that all GaussMarkov assumptions hold when interpreting the estimates (Answer in less than 50 words for each parameter you interpret)