The coefficient of absorption (COA) for a clay brick is the ratio of the amount of cold water to the amount of boiling water that the brick will absorb. The article "Effects of Waste Glass Additions on the Properties and Durability of Fired Clay Brick" (S. Chidiac and L. Federico, Can J Civ Eng, 2007:1458-1466) presents measurements of the (COA) and the pore volume (in cm3/g) for seven bricks. The results are presented in the following table.
Pore volume COA
1.750..............................0.80
1.632..............................0.78
1.594..............................0.77
1.623..............................0.75
1.495..............................0.71
1.465..............................0.66
1.272..............................0.63
a. Compute the least-squares line for predicting COA from pore volume.
b. Compute the error standard deviation estimate s.
c. Compute a 95% confidence interval for the slope.
d. Find a 95% confidence interval for the mean COA for bricks with pore volume 1.5 cm3/g.
e. Can you conclude that the mean COAfor bricks with pore volume 1.5 cm3/g is less than 0.75? Perform a hypothesis test and report the P-value.
f. Find a 95% prediction interval for the COA of a particular brick whose pore volume is 1.5 cm3/g.