Chapter 12, Problem 28PT4

To determine

To find the correct 95% confidence interval for the slope of the regression line.

Answer to Problem 28PT4

  $(e)20.230\pm 3.91$

Explanation of Solution

Given:

  

Formula:

Confidence interval for slope is,

  $(Coefficient(b)\mp t_c\times S{E}_b)$

The confidence level = 0.95

So, level of significance = $\alpha$ = 0.05

First need to find critical t value.

tc = 2.306 …Using excel formula, =TINV(0.05,8)

Using formula, 95% confidence interval for the slope of the regression line.

  $(20.230\pm 2.306\times 1.695)=(20.230\pm 3.91)$