申論題

8. In a hypothetical experiment, a spring is hung vertically with the top end fixed, and weights are hung one at a time from the other end. After each weight is hung, the length of the spring is measured. The following table presents the results of the hypothetical experiment.
Measured lengths of a spring under various loads

The equation of the least-squares line is y =x. Substituting the computed values for (unloaded length of the spring) and (spring constant), we obtain y = 4.9997 + 0.2046x.

(d) Find a 95% confidence interval of the length of a spring under a load of 1.4lb. The 95% confidence interval of the length of a spring under a load of 1.4lb is__(P)__.