Checking Error Assumptions in Minitab
It is a good idea to store standardized residuals in the data worksheet
Stat Regression Regression
In regression dialogue box, click Storage.
Check Standardized Residuals under Diagnostic Measures
Checking for randomness and constant variance
To produce a scatterplot of the standardized residuals against the fitted values:
Stat Regression Regression
Click Graphs and check the box next to Residuals versus fits
To produce a scatterplot of the standardized residuals against each of the
independent variables:
Stat Regression Regression
Under Residuals versus the variables, enter each of the independent variables
Checking for normality
To produce graphs as part of the regression analysis:
Stat Regression Regression
Click Graphs and check the boxes next to Histogram of Residuals and Normal Plot of
Residuals
To see an idealized normal density plot overtop of the histogram of residuals:
Make sure you have stored the standardized residuals in the data worksheet (see above.)
Graph Histogram With Fit OK.
Under Graph variables, select the column in which the residuals were stored (something
like SRES1), then click OK.
To create a stem and leaf plot
Make sure you have stored the standardized residuals in the data worksheet (see above.)
Graph Histogram With Fit OK.
Under Graph variables, select the column in which the residuals were stored (something
like SRES1), then click OK.