1. Overlap of Confidence Intervals: In the article "On Judging the Significance of Differences by Examining the Overlap Between Confidence Intervals," by Schenker and Gentleman (American Statistician, Vol. 55, No. 3), the authors consider sample data in this statement: "Independent simple random samples, each of size 200, have been drawn, and 112 people in the first sample have the attribute, whereas 88 people in the second sample have the attribute."
2. Construct a 95% Wald confidence interval estimate of the difference .What does the result suggest about the equality of and (i.e. )?

95% Wald confidence interval: _______ < < _______

Because the confidence interval limits _____________ (contain or do not contain) 0, it appears that (i.e. ___________ (can or cannot) be rejected.

1. Use the methods of Modules 2 and 3 to construct individual 95% Wald confidence interval estimates for each of the two population proportions. After comparing the overlap between the two confidence intervals, what do you conclude about the equality of and ?

95% Wald confidence interval: _______ < < _______

95% Wald confidence interval: _______ < < _______

Because the confidence intervals _______ (do or do not) overlap, it appears that (i.e. ) _________ (can or cannot) be rejected.

1. Use a 0.05 significance level to test the claim that the two population proportions are equal. What do you conclude?

_____ (i.e. )

_____ (i.e. )

Chi-Squared Test Statistic: _______

P-value = _______

Conclusion: Reject or Fail to reject

There _______ (is or is not) sufficient evidence to reject (i.e. .

1. Based on the preceding results, what should you conclude about the equality of and ?Which of the three preceding methods is least effective in testing for the equality of and ?

Conclusion: Reject or Fail to reject

Least effective method: Using the ____________ between the individual confidence intervals.