The Quality of a product depends on temperature and Pressure (in PSI). Use the 27 observations in the table and answer the following questions:
|
Quality
|
Temp
|
PSI
|
|
Quality
|
Temp
|
PSI
|
|
50.80
|
80
|
50
|
|
97.40
|
90
|
55
|
|
50.70
|
80
|
50
|
|
70.90
|
90
|
60
|
|
49.40
|
80
|
50
|
|
68.80
|
90
|
60
|
|
93.70
|
80
|
55
|
|
71.30
|
90
|
60
|
|
90.90
|
80
|
55
|
|
46.60
|
100
|
50
|
|
90.90
|
80
|
55
|
|
49.10
|
100
|
50
|
|
74.50
|
80
|
60
|
|
46.60
|
100
|
50
|
|
73.00
|
80
|
60
|
|
69.80
|
100
|
55
|
|
71.20
|
80
|
60
|
|
72.50
|
100
|
55
|
|
63.40
|
90
|
50
|
|
73.20
|
100
|
55
|
|
61.60
|
90
|
50
|
|
38.70
|
100
|
60
|
|
63.40
|
90
|
50
|
|
42.50
|
100
|
60
|
|
93.80
|
90
|
55
|
|
41.40
|
100
|
60
|
|
92.10
|
90
|
55
|
|
|
|
|
1. Fit a first-order model to the data (make sure you include both independent variables.)
2. Report the equation of the model.
3. Interpret the estimated regression coefficients.
4. Report the coefficient of determination and the standard error of estimate for the first-order model. Based on these, how good is the model?
5. Fit an interaction model to the data.
6. Report the coefficient of determination and the standard error of estimate for the interaction model. Based on these, how good is the model?
7. Fit a complete second-order model to the data.
8. Report the coefficient of determination and the standard error of estimate for the complete second-order model. Based on these, how good is the model?
9. Which of the three models do you prefer? Why? Explain.