EXAMPLE 6 Confidence interval for the slope

Construct a 95% confidence interval for the slope of the population regression equation for the memory-test data in Example 5.

Solution

The regression assumptions were verified in Example 5, where we found:

  • ,
  • , and
  • .

From the table (Appendix Table D), we find that, for 95% confidence, for degrees of freedom is . So, our margin of error is

The 95% confidence interval for is then given by

NOW YOU CAN DO

Exercises 23–30.