numpy - polynomial regression using python

Question

From what I understand polynomial regression is a specific type of regression analysis, which is more complicated than linear regression. Is there a python module which can do this? I have looked in matplotlib, scikit and numpy but can only find linear regression analysis.

And it is possible to work out the correlation coefficient of a non-linear line?

Answer 1

Have you had a look at NumPy's polyfit? See reference.

From their examples:

>>> import numpy as np
>>> x = np.array([0.0, 1.0, 2.0, 3.0,  4.0,  5.0])
>>> y = np.array([0.0, 0.8, 0.9, 0.1, -0.8, -1.0])
>>> z = np.polyfit(x, y, 3)
>>> z
[ 0.08703704 -0.81349206  1.69312169 -0.03968254]