Hello, could you explaine to a newby when / in which cases does it apply polinomial (non linear) regressions?
I know that they generate a curve line which fits the datas. What I don’t understand is when is used this kind of regression.
In linear regression we have IV and DV and we want to extimate a correlation between, and the regression line which fits the data is the expression of this correlation and the Least squared computation which produce a linear rect, But how and WHEN do it originates a curvilinear line?
In which cases? Could you make an example? with an IV and a DP. V ?