# Same model two genders

I have created a multiple regression model that checks if final result is explained by following predictor variables:

Time spent studying Class attendance (%) Cash spend on extra materials and classes etc.

Now I have a group of 50 boys and a group of 50 girls. I run my model for each gender independently. Can I compare coefficient of (for example) Class attendance for boys with coefficient of same variable for girls and say:

"Boys final results are less dependent on their class attendance than girls?"

If not how can I compare them?

## 1 Answer

Put your 100 children's data together. Add one variable: Gender = 1 for male, = 0 for female. Call this variable $$Z$$.

Fit the following model: $$Y = \beta_0 + \beta_1 X_1 ...+\beta_k X_k + \alpha_0 Z + \alpha_1 ZX_1 ...+\alpha_k ZX_k +\epsilon$$ where $$X_1,...,X_k$$ are Time spent studying Class attendance (%) Cash spend on extra materials and classes etc..

Then you can check the $$\alpha$$s to see is there difference between male and female on their results on $$X$$. For example if $$X_1$$ is Class attendance, then $$\alpha_1$$ will tell you the difference of the effect of Class attendance on the results between male and female.