Apply Procedure 14.2 to find and interpret a confidence interval, at the specified confidence level, for the slope of the population regression line that relates the response variable to the predictor variable

Procedure 14.2

Purpose To find a confidence interval for the slope, β₁, of the population regression line

Assumptions The four assumptions for regression inferences

Step 1

For a confidence level of 1 — α, use to find t_a/2 with df = n — 2.

Step 2

The endpoints of the confidence interval for ß₁ are

Step 3

Interpret the confidence interval.

Refer to Exercise 14.62; 90%.

Exercise 14.62

Following are the data on age of fetuses  and length of crown-rump from Exercise 14.26. Use α = 0.10.

b = t/2. Se Sxx