The data shown in Table 12-22 represent the thrust of a jet-turbine engine (y) and six candidate regressors: x1 =

primary speed of rotation, x2 secondary speed of rotation, x3 fuel flow rate, x4 pressure, x5 exhaust temperature, and x6 ambient temperature at time of test.

(a) Fit a multiple linear regression model using x3 fuel flow rate, x4 pressure, and x5 exhaust temperature as the regressors.

(b) Test for significance of regression using 0.01. Find the P-value for this test. What are your conclusions?

(c) Find the t-test statistic for each regressor. Using 0.01, explain carefully the conclusion you can draw from these statistics.

(d) Find R2 and the adjusted statistic for this model.

(e) Construct a normal probability plot of the residuals and interpret this graph.