The following model was used to relate E1y2 to a single qualitative variable with four levels: E1y2 = b0 + b1x1 + b2x2 + b3x3 where x1 = e 1 0 if level 2 if not x2 = e 1 0 if level 3 if not x3 = e 1 0 if level 4 if not This model was fit to n = 40 data points, and the following result was obtained: yn = 57 + 18x1 - 62x2 + 101x3

a. Use the least squares prediction equation to find the estimate of E(y) for each level of the qualitative independent variable.

b. Specify the null and alternative hypotheses you would use to test whether E(y) is the same for all four levels of the independent variable. Applying the Concepts—Basic