Python Data Analysis Cookbook

Visualizing the goodness of fit

We expect, or at least hope, that the residuals of regression are just random noise. If that is not the case, then our regressor may be ignoring information. We expect the residuals to be independent and normally distributed. It is relatively easy to check with a histogram or a QQ plot. In general, we want the mean of the residuals to be as close to zero as possible, and we want the variance of the residuals to be as small as possible. An ideal fit will have zero-valued residuals.

How to do it...

1. The imports are as follows:

   import numpy as np
   import matplotlib.pyplot as plt
   import dautil as dl
   import seaborn as sns
   from scipy.stats import probplot
   from IPython.display import HTML

2. Load the target and predictions for ...