Conduct Regression Error Normality Tests

Conduct Regression Error Normality Tests

Minitab®  – Procedure

If you haven't already done so, store the residuals on which you want to conduct the Ryan Joiner correlation test.

  1. Select Stat > Regression > Regression > Fit Regression Model...
  2. Specify the response and the predictor variable(s).
  3. Select Storage... Under Diagnostic Measures, select the type of residuals (and/or influence measures) that you want to store. Select OK.
  4. Select OK. The requested residuals (and/or influence measures) will be stored in your worksheet.

Once Minitab has stored the residuals in your worksheet:

  1. Select Stat > Basic Statistics > Normality Test...
  2. In the box labeled Variable, specify the name of the variable containing the residuals (Minitab names it something like RESI1, RESI2, ...).
  3. Under Tests for Normality, select Anderson-Darling, Ryan-Joiner, or Kolmogorov-Smirnov.
  4. Select OK. A new graph window containing the requested normal probability plot should appear.

Example

The data set adaptive.txt contains the Gesell adaptive scores and ages (in months) of n = 21 children with cyanotic heart disease. Upon regressing the response y = score on the predictor x = age, use the resulting residuals to test whether or not the error terms are normally distributed.

Minitab Dialog Boxes

Minitab regression dialog box

Minitab regression dialog box - storage

Minitab Normality test dialog box

Sample Output

Probability Plot of RESI1

Video Review

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