The article "Application of Analysis of Variance to Wet Clutch Engagement" (M. Mansouri, M. Khonsari, et al., Proceedings of the Institution of Mechanical Engineers, 2002:117-125) presents the following fitted model for predicting cutch engagement time in seconds (y) from engagement starting speed in m/s (x1), maximum drive torque in Nm(x2), system inertia in kgm2 (x3), and applied force rate in kN/s (x4).

y = −0.83 + 0.017x1 + 0.0895x2 + 42.771x3 + 0.02x4 − 0.0043x2x4

The sum of squares for regression was SSR = 1.08613 and the sum of squares for error was SSE = 0.036310. There were 44 degrees of freedom for error.
Required:
a. Predict the clutch engagement time when the starting speed is 20 m/s, the maximum drive torque is 17 N · m, the system inertia is 0.006 kg · m2, and the applied force rate is 10 kN/s.
b. Is it possible to predict the change in engagement time associated with an increase of 2 m/s in starting speed? If so, find the predicted change. If not, explain why not.
c. Is it possible to predict the change in engagement time associated with an increase of 2 N · m in maximum drive torque? If so, find the predicted change. If not, explain why not.
d. Compute the coefficient of determination R2.
e. Compute the F statistic for testing the null hypothesis that all the coefficients are equal to 0. Can this hypothesis be rejected?