In the Initial Test of the Salk Vaccine for Polio $\alpha = 0.01$

Essay

In the initial test of the Salk vaccine for polio, 400,000 children were randomly selected and divided into two
groups of 200,000. 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 receiving the
placebo, 115 later developed polio. Test the claim that the Salk vaccine is effective in lowering the polio rate.
Use $\alpha = 0.01$