An experiment was conducted to investigate the effect of temperature (T) and pressure (P) on the yield y of a chemical. Each of the two factors, temperature and pressure, was held constant at two levels—T at 50° and 70°, P at 10 pounds per square inch and 20 pounds per square inch—and the yield of each of the four combinations was measured. The results are shown in the accompanying table.

a. Fit the linear model 

E(y) = β_o + β₁x₁ + β₂x₂ + β₃x₁x₂

to the data.

b. Conduct a test of overall model adequacy. Use α = .01.

c. Is there evidence of interaction between temperature and pressure? Test using α = .01.    

Transcribed Image Text:

CHEMYLD Temperature Pressure Yield 50 10 24.5 50 10 26.0 50 20 28.4 50 20 28.1 70 10 22.1 70 10 20.8 70 20 16.7 70 20 15.3