- What happens if linearity is violated?
- How do you know if assumption of linearity is met?
- How do you verify linearity?
What happens if linearity is violated?
Linearity Linear regression is based on the assumption that your model is linear (shocking, I know). Violation of this assumption is very serious–it means that your linear model probably does a bad job at predicting your actual (non-linear) data.
How do you know if assumption of linearity is met?
The linearity assumption can best be tested with scatter plots, the following two examples depict two cases, where no and little linearity is present. Secondly, the linear regression analysis requires all variables to be multivariate normal. This assumption can best be checked with a histogram or a Q-Q-Plot.
How do you verify linearity?
We can check the linearity of the data by looking at the Residual vs Fitted plot. Ideally, this plot would not have a pattern where the red line (lowes smoother) is approximately horizontal at zero. In the above plot we can see that there is a clear pattern in the residual plot.