Group sample sizes of 104 in group one and 104 in group two achieve 85% power to detect a difference between the group proportions of -0.2000. The group two proportion is 0.5000. The group one proportion is assumed to be 0.5000 under the null hypothesis and 0.3000 under the alternative hypothesis. The test statistic used is the two-sided Z test (unpooled). The significance level of the test was targeted at 0.0500. The significance level actually achieved by this design is not available.