Consider the following data from Exercise 12.13. y (wear) x 1 (oil viscosity) x 2 (load) 193 1.6 851 230 15.5 816 172 22.0 1058 91 43.0 1201 113 33.0 1357 125 40.0 1115 (a) Estimate σ 2 using multiple...

Consider the following data from Exercise 12.13.

(a) Estimateσ
₂ using multiple regression ofyonx
₁ andx
₂.

(b) Compute predicted values, a 95% confidence interval for mean wear, and a 95% prediction interval for observed wear ifx
₁ = 20 andx
₂ = 1000.

Exercise 12.13A study was performed on a type of bearing to find the relationship of amount of wearytox
₁ = oil viscosity andx
₂ = load. The following data were obtained. (FromResponse Surface Methodology, Myers, Montgomery, and Anderson-Cook, 2009.)

(a) Estimate the unknown parameters of the multiple linear regression equation

μ_Y|x
₁
,x
₂ =β
₀ +β
₁
x
₁ +β
₂
x
₂
.

(b) Predict wear when oil viscosity is 20 and load is 1200.