Researchers at Dow Chemical Co. investigated the effect of tablet surface area and volume on the rate at which a drug is released in a controlled-release dosage (Drug Development and Industrial Pharmacy, Vol. 28, 2002). Six similarly shaped tablets were prepared with different weights and thicknesses, and the ratio of surface area to volume was measured for each. Using a dissolution apparatus, each tablet was placed in 900 milliliters of deionized water, and the diffusional drug release rate (percentage of drug released divided by the square root of time) was determined. The experimental data are listed in the table below.


a. Fit the simple linear model, E(y) = β0 + β1x, where y = release rate and x = surface-area-to-volume ratio.
b. Interpret the estimates of β0, and β1.
c. Predict the drug release rate for a tablet that has a surface area/volume ratio of .50.
d. Comment on the reliability of the prediction in part c.