Hello everybody,

I have a question simply to the way of how to calculate something:

I have variable V, which is continuous, and variable dummy, which is a factor variable.

First I have the regression:

Code:
 xtreg P c.lnV##i.dummy lnSa Ratio lnAge Closely i.year, fe vce(cluster ID)
but now I want to add the squared term of V! How do I do that? I would do:

Code:
 xtreg P lnV lnV_sq dummy i.dummy#c.lnV i.dummy#c.lnV_sq  lnSa Ratio lnAge Closely i.year, fe vce(cluster ID)
But I also read I have to center or standardize the variables first in order to not increase multicollinearity too much, so when do I do what with the variables?

egen lnV_std = std(lnV)
egen lnV_std_sq = std(lnV*lnV)
egen Interaction1 = std(lnV)*dummy
egen Interaction2 = std(lnV*lnV)*dummy

Is this the right order of squaring, standardizing, taking the log and multiplying?

Thank you very much for your help