I want to conduct a linear regression (in matlab) using rolling monthly returns; the aim is to give me a prediction for the next monthly rolling period return.
return calculation:
$$\mbox{return}(t) = \dfrac{\mbox{Price}(t) - \mbox{Price}(t-30)}{\mbox{Price}(t-30)}.$$
regression:
$$\mbox{return}(t+1) = a + b_1f_1 + b_2f_2 +b_3f_3+ e.$$
My question is what is the best way to conduct a linear regression using a rolling return with a time horizon greater than $1$ day?
Thanks!