Chapter 11.2, Problem 13E

a.

To determine

Draw the scatter diagram of the data.

Explain whether the liner regression model seem reasonable in this situation or not.

b.

To determine

Find the least squares estimates of the slope and intercept in the simple regression model.

Find the estimate of ${\sigma }^2$.

c.

To determine

Find the mean share strength of a motor made from propellant that is 20 weeks old.

d.

To determine

Find the fitted ${\widehat{y}}_i$ values for each observed value $y_i$.

Construct the graph of ${\widehat{y}}_i$ corresponding to the observed value $y_i$

Comment on the shape of the diagram if the linear relationship between shear strength and age were perfectly deterministic.

Explain whether the diagram actually obtained indicate that age is reasonable choice of regressor variable in this model.