The staff of a test kitchen is attempting to determine the baking time,
y, of a roast, i.e., the time it takes the internal temperature of the roast to reach 165°F, using two variables, the temperature setting of the oven,
x1, and the weight of the roast,
x2, in pounds. The data for 24 roasts are shown below.

a. | Fit a complete second-order model to the data. |
b. | Do the data provide sufficient evidence to indicate that the second-order terms contribute |
information for the prediction of
y? State the null and alternative hypotheses and the test statistic.