i´ve got a technical question for using the lm-function.
I would like to make a linear regression with the following shape:
∆Y_t= -φε_(t-1)+ β ∆X_t+ u_t
with u_t = residuals.
I want to estimate the parameters φ and β.
I already know, that by adding " -1 " in the formula of the lm-function, i will get an estimation without an intercept.
My problem is the "-" before the φ. How do i need to build the formula in this case?
My first attempt was like this:
lm(∆Y_t ~ -ε_(t-1) + ∆X_t - 1). The result was a model without consideration of the variable ε_(t-1).