Independent Samples: Comparing Proportions Lecture 42 Section 11.5 Fri, Apr 8, 2005

Confidence Intervals A confidence interval for p1 – p2 is of the form

Confidence Intervals Since we are trying to estimate the difference between p1 and p2, it would not make sense to use the pooled estimate of.

Example Re-do Example 11.8, p. 669, as a confidence interval problem.

Confidence Intervals on the TI-83 Press STAT. Select 2-PropZInt. A window appears. Enter x1. Enter n1. Enter x2. Enter n2.

Confidence Intervals on the TI-83 Enter the confidence level. Select Calculate. Press ENTER.

Confidence Intervals on the TI-83 A window appears with the following information. The confidence interval for p1 – p2. The value of p1^. The value of p2^. n1. n2.

Example Re-do Example 11.8, p. 669, using the TI-83.

Let’s Do It! Let’s do it! 11.7, p. 671 – HMOs on the Rise.