Minitab Help 6: MLR Model Evaluation

Minitab 18

Minitab®

Heart attacks in rabbits

  • Perform a linear regression analysis of Infarc on Area, X2 (early cooling), and X3 (late cooling).
  • Click "Storage" in the regression dialog and check "Fits" to store the fitted (predicted) values.
  • To create a scatterplot of the data with points marked by group and three lines representing the fitted regression equation for each group:
    • Select Calc > Calculator, type "FITS_1" in the "Store result in variable" box, and type "IF('Group'=1,'FITS')" in the "Expression" box. Repeat for FITS_2 (Group 2) and FITS_3 (Group 3).
    • Create a basic scatter plot but select "With Groups" instead of "Simple." Select Infarc as the "Y variable," Area as the "X variable," and Group as the "Categorical variable for grouping."
    • Select Editor > Add > Calculated Line and select "FITS_1" to go in the "Y column" and "Area" to go in the "X column." Repeat for FITS_2 (Group 2) and FITS_3 (Group 3).

Student heights and GPAs

  • Perform a linear regression analysis of gpa on height.
  • Create a fitted line plot to create a scatterplot of the data with a fitted simple linear regression line. Select Editor > Add > Reference Lines to add a horizontal line at the mean of gpa.
  • SSE for the full model is in the SSE row of the Anova table.
  • SSE for the reduced model is in the Total row of the Anova table.
  • The overall F statistic and p-value are in the Regression row of the Anova table.

Skin cancer mortality

  • Perform a linear regression analysis of Mort on Lat.
  • Create a fitted line plot to create a scatterplot of the data with a fitted simple linear regression line. Select Editor > Add > Reference Lines to add a horizontal line at the mean of Mort.
  • SSE for the full model is in the SSE row of the Anova table.
  • SSE for the reduced model is in the Total row of the Anova table.
  • The overall F statistic and p-value are in the Regression row of the Anova table.

Alcoholism and muscle strength

  • Perform a linear regression analysis of strength on alcohol.
  • SSE for the full model is in the SSE row of the Anova table.
  • SSE for the reduced model is in the Total row of the Anova table.
  • The overall F statistic and p-value are in the Regression row of the Anova table.

Allen cognitive level study

  • Perform a linear regression analysis of ACL on:
    • Vocab (with default adjusted sums of squares).
    • Vocab and SDMT (with adjusted sums of squares).
    • Vocab and SDMT (click "Options" to switch to sequential sums of squares).
    • SDMT (click "Options" to switch back to adjusted sums of squares).
    • SDMT and Vocab (with adjusted sums of squares).
    • SDMT and Vocab (click "Options" to switch to sequential sums of squares).
    • SDMT, Vocab, and Abstract (with sequential sums of squares).

Heart attacks in rabbits (revisited)