The strength of paper used in the manufacture of cardboard boxes (y) is related to the percentage of hardwood concentration in the original pulp (x). Under controlled conditions, a pilot plant...

The strength of paper used in the manufacture of cardboard boxes (y) is related to the percentage of hardwood concentration in the original pulp (x). Under controlled conditions, a pilot plant manufactures 16 samples, each from a different batch of pulp, and measures the tensile strength. The data are shown in the table that follows:
(a) Fit a simple linear regression model to the data.
(b) Test for significance of regression using a = 0.05.
(c) Construct a 90% confidence interval on the slope B1.
(d) Construct a 90% confidence interval on the intercept B0.
(e) Construct a 95% confidence interval on the mean strength at x = 2.5.
(f) Analyze the residuals and comment on model adequacy.