Checking Model Conditions for Multiple Regression

Consistency in the spread of residuals around the regression line, checked by construction of a residual plot

Constant Variability of Residuals

Residuals must not be influenced by one another, difficult to assess but can make use of time-series plots

Independent Residuals

Each predictor variable linearly relates to the outcome, directly checked by linear plot between each predictor and the response variable

Linear Relationship

Graphical tools to assess regression assumptions

Diagnostic plots

Extreme data points that deviate from the overall pattern

Outliers

Changing data using mathematical functions to simplify relationships; however, the interpretation of the plot will be equally complicated

Transformations