Assume we estimate a multiple regression model for the response variable y. We have the following relationships in this model. The 1st numerical variable is in the model as a linear relationship. The 2nd numerical variable is in the model with a quadratic relationship to y. . There is one categorical variable with 4 levels. The relationship between the first numerical variable and the response y depends on the levels of the categorical variable. Assume this model is estimated with n=310 observations. What is the numerical Error Degrees of Freedom.