In the initial test of the salk vaccine for polio, 400 children were selected and divided into 2 groups of 200. one group was vaccinated with the salk vaccine while the second group was vaccinated with a placebo. of those vaccinated with the salk vaccine, 33 later developed polio. of those vaccinated with the placebo, 115 later developed polio. test the claim that the salk vaccine is effective in lowering the rate of polio. use significance .01 and assume that the data is distributed normally.

a. what is the appropriate set of hypothesis (H0, H1)?

b. what is the correct proportions(psalk, p-placebo)?

c. what is the correct value of the test statistic?

d. what is the correct confidence integral?

e. was the salk vaccine effective at reducing the rate of polio