It is traditional practice in Egypt to withhold food from children with diarrhea. Because it is known that feeding children with this illness reduces mortality, medical authorities undertook a nationwide program designed to promote feeding sick children. To evaluate the impact of the program, surveys were taken before and after the program was implemented. In the first survey, 457 of 1003 surveyed mothers followed the practice of feeding children with diarrhea. For the second survey, 437 of 620 surveyed followed this practice.
a) Assume that the data come from two independent samples. Test the hypothesis that the program was effective, that is, the practice of feeding children with diarrhea increased between the time of the first study and the time of the second. State H0 and Ha, give the test statistic (a test for proportions using Z) and its p-value, and summarize your conclusion.
b) Present the data in a two-way table. Can the ƒÓ2 statistic test your hypotheses? Yes or No. Why?
c) Obtain a 95% confidence interval (two-tailed) for the difference in proportions.