Let's say I have 3 features in my ols model as below.
model = sm.ols(formula='y ~ a + b + c', data=df)
Question 1. If I want to transform the feature 'a' as polynomial 3 degree, then should I just add I(a**2) and I(a**3)?
Question 2. What about if I want to transform the feature 'a' as 3 degree and the feature 'b' as 2 degree.