In a chemical engineering experiment dealing with heat transfer in a shallow fluidized bed, data are collected on the following four regressor variables: fluidizing gas flow rate, lb/hr

(x ); supernatant gas flow rate, lb/hr (x ); supernatant gas inlet nozzle opening, millimeters (x ); and supernatant gas inlet temperature, °F (x ). The responses measured are heat transfer efficiency (y ) and thermal efficiency (y ). The data are as follows:

1 2 3

1 2 3

4 1 2 Consider the model for predicting the heat transfer coefficient response 1. Compute PRESS and for the least squares regression fit to the model above.

2. Fit a second-order model with x completely eliminated (i.e., deleting all terms involving x ). Compute the prediction criteria for the reduced model. Comment on the 4

4 appropriateness of x for prediction of the heat transfer coefficient.

3. Repeat parts

(a) and

(b) for thermal efficiency.