# Factorial Analysis Using Multiple Linear Regression (With Interactions) in MINITABTM

## Chapter 9, Printout 4

1. Launch MINITAB.

2. Enter the data.

• Name Column C1 by clicking the column header below the label "C1" and typing, "xa1." Then, in rows 1-11, enter the 11 values for xa1 from the "xA1" column in Table 9.20 (p. 709).

Note: you will have to enter each xa1 value once for each corresponding y-value in Table 9.20. The same is true for xa2 and xb1. See the screenshot at the end of this step for clarification if necessary.

• Name Column C2 "xa2" and enter the 11 values for xa2 from the "xA2" column in Table 9.20.

• Name Column C3 "xb1" and enter the 11 values for xb1 from the "xb1" column in the table.

• Name Column C4 "xa1*xb1."

• Select "Calc --> Calculator."

• Fill out the resulting dialog box as follows:

Input Type Label Value
Store result in variable: 'xa1*xb1'
Expression: 'xa1' * 'xb1'

Screenshot:

• Name Column C5 "xa2*xb1."

• Select "Calc --> Calculator."

• Fill out the resulting dialog box as follows:

Input Type Label Value
Store result in variable: 'xa2*xb1'
Expression: 'xa2' * 'xb1'

Screenshot:

• Click "OK."

• Name Column C6 "y" and enter 11 values for y from the "y" column in Table 9.20.

Screenshot:

3. Compute the multiple linear regression.

• Select "Stat --> Regression --> Regression."

• Fill out the resulting dialog box as follows:

Input Type Label Value
Response: y
Predictors: x1 x2 x3 'xa1*xb1' 'xa2*xb1'

Screenshot:

• Before closing the dialog box, click "Results."

• In the dialog box that follows, click the radio button next to the label, "In addition, the full table of fits and residuals."

Screenshot:

• Click "OK" to close the "Results" dialog box.

• Click "OK" in the "Regression" dialog box.

MINITAB displays summary information, including the regression equation and a table of fits and residuals.

Screenshot: