77 The model E(y) = b0 + b1 x1 + b2 x2 + b3 x3, where

was used to relate E ( y ) to a single qualitative variable with four levels. This model was fitted to n = 30 data points and the following result was obtained:
yn = 10.2 - 4x1 + 12x2 + 2x3

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.

Transcribed Image Text:

x1 x2 ===== x3= 10 (1 0 lo 10 if level 2 if not if level 3 if not if level 4 if not