127 A chemical engineer is investigating how the amount of c

12-7. A chemical engineer is investigating how the amount of conversion of a product from a raw material (y) depends on reaction temperature (%) and the reaction time (x). He has developed the following regression models: 1, y=100 + 2x1+4x2 2. y=95 + 1.5 +3x2 + 2x1x2 Both models have been built over the range 0.5Sx2 S10. (a) What is the predicted value of conversion when x2 2? Repeat this calculation for x2-8. Draw a graph of the pre- dicted values for both conversion models. Comment on the effect of the interaction term in model 2.

Solution