1. Click Stat<<ANOVA<<General Linear Model<<Fit General Linear Model

Go to the Session window and find the Analysis of Variance table. Look at the P-

The P-

In the Session Window we find that the Analysis of Variance table only has significant terms. As we have reduced the number of terms the Lack-

1. Click Stat<<ANOVA<<General Linear Model<<Fit General Linear Model or press Ctrl+E.

2. Complete the menu as shown below and then click on the Model button.

3. Press the Ctrl key and click on each of the factors to highlight all of them. Then go the Interactions through order selector and change it to 3. Then click on the Add button.

4. Click OK & OK to execute the procedure.

4. Click on the Graphs button and select the radio button for the Four-

5. Click OK and OK again to execute the procedure.

2. Remove Material as a Factor and then click on the Model button.

3. Minitab will remove all interactions apart from the ‘Temp*Press’ interaction. Remove that by pressing the Default button. Then return to the root GLM menu by clicking OK once.

The R-

As only Temp and Press are the significant factors we can use the Main Effects plot to establish which setting would give the greatest strength; Temp=115, Press=7.

The VIFs are less than 5 which means that our model will not suffer from stability issues.

Below that we have the regression equation which we can use to predict values of strength.

Finally, to validate the model we must check the residual plots. Find the Four-

Starting the with Normal Probability plot we want to know if it can be covered with a thick pencil and it can.

The Histogram is not extremely skewed.

The residuals are equally spaced around the zero line on the Versus Fits plot.

The data was collected in time order so using this plot is a valid check.

We find no patterns in the residuals that would alert us to any problems.