Conduct a Lack of Fit Test

Minitab 18

Minitab®

Procedure Section

  1. Select Stat >> Regression >> Regression ...  >> Fit Regression Model ... 
  2. Specify the response and the predictor(s).
  3. Minitab automatically recognizes replicates of data and produces the Lack of Fit test with Pure error by default.
  4. Select OK. The output will appear in the session window.

Example Section

The data set bluegills.txt contains the lengths (in mm) and ages (in years) of n = 78 bluegill fish. Is there sufficient evidence to conclude that there is a lack of linear fit between y = length and x = age of bluegill fish?

Minitab Dialog Box

Minitab 17 regression dialog box

Sample Output

Regression Analysis: length versus age

Analysis of Variance
Source DF   Adj SS Adj MS   F-value   P-value
Regression 1 32966    32965.8 210.66    0.000
     age 1 32966    32965.8 210.66    0.000
Error 76 11893 156.5    

     Lack-of-Fit

4 3080

770.0

6.29    0.000
     Pure Error 72 8813 122.4    
Total 77 44859      

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