Model to test seasonality

[DuarteR]

Hi,

My dissertation is about funds seasonality and the model that I am using is an OLS with dummies to check if january have a return greater than the remaining period:

Rt = B0 + B1 Dmt + Ut

Rt is the return on funds
B0 is the intercept
Dmt is the dummy variable. The value 1 corresponding to January and 0 otherwise
Ut is error term

What tests do I have to run? I am checking for heteroscedasticty(White test) and serial correlation (Durbin Watson test). Do I need to run other tests?

Thank you

Any feedback you could give me would be greatly appreciated

Duarte