In: Statistics and Probability
What can a plot of the residuals alert us about?
Solution :-
A residual value is a measure of how much a regression line vertically misses a data point. Regression lines are the best fit of a set of data. If we think of the lines as averages; a few data points will fit the line and others will miss.
A residual plot has the Residual Values on the vertical axis; the horizontal axis displays the independent variable.
Residual plot is typically used to find problems with regression. Some data sets are not good candidates for regression, including:
These problems are more easily seen with a residual plot than by looking at a plot of the original data set. Ideally, residual values should be equally and randomly spaced around the horizontal axis.
In one word, the analysis of residuals is a powerful diagnostic tool, as it will help to assess, whether some of the underlying assumptions of regression have been violated.