just e) through f)

4. In this class, we have discussed the Salk vaccine trial several times. In the random- ized controlled, double-blind portion of the trial, the results were as follows: Group Size Polio cases per 100,008 Treatment 200,000 28 Control 200,000 71 (a) Is the above table a contingency table? If not, create one from the data above. (b) Perform a two-sample proportions test at the .05 level of significance, and inter- pret. Be sure to report the null and alternative hypotheses, your test statistic, and the p-value calculated. Notes Please include relevant Ercel syntar (c) Perform a x2 test at the 05 level of significance, and interpret. Be sure to report the null and alternative hypotheses, your test statistic, and the p-value calculated. Note: Please include relevant R syntax (d) How do the results from the two sample proportions test and the x' test com- pare? (e) Extra credit (2 points) Calculate a 95% confidence interval for the true odds ratio. Interpret. (f) On the basis of this study, what should the Public Health Service (the or- ganization that carried out the study) conclude about the significance (both statistical and clinical) of the polio vaccine? (g) Is it safe to conclude that the vaccine is causing a reduction in polio, or could there be hidden confounders