Measuring the height of a tree is usually more difficult than measuring the diameter of the tree. Therefore, many researchers use regression models to predict the height of a tree from its diameter measured at 4 feet 6 inches from the ground. The following computer output shows the results of a linear regression based on the heights, in feet, and the diameters, in inches, recorded from 31 felled trees. Estimate Std Error t-value Pr(>|t|)
Intercept 62.031 4.383 14.15 0.0000
Diameter 1.054 0.322 0.0028 3.27

Required:
What is a 95 percent confidence interval for the slope of the population regression line?