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.

(c) Find a 99% confidence interval for the unloaded length of the spring, . The 99% confidence interval for the unloaded length of the spring is __(O)__.