In an article in /EFE Transactions on Instrumentation and Measurement $(2001,$ Vol $.50,$ pp. $2033-2040)$ powdered mixtures of coal and limestone were analyzed for permittivity. The crrors in the density measurement was the response.(a) Fit a multiple linear regression model to these data with the density as the response.
(b) Estimate $\sigma^{2}$ and the standard errors of the regression coefficients.
(c) Use the model to predict the density when the dielectric constant is 2.5 and the loss factor is $0.03 .$