Hi,
I have a dataset with strictly proportional data and all the variables used in my fractional regression are proportions. My question is more of a theoretical one - does the fracreg logit command still assume that my model is linear in its parameters? And if it is, how do I know which explanatory variable should be squared in my regression model? my data is an aggregate of binary responses globally and are random for the most part.
I mean the standard (PRATE I X) = B, + BzMRATE +.... etc equation - help would be hugely appreciated.

Edit:
Say i wanted to use a logit quasimaximum likelihood estimation as in the attached picture, how would i then write the equation?