Answer
a. 90 percent
b. The claim should be accepted.
c. The p-value and critical value methods
Work Step by Step
a. We want a .05 significance level, so our confidence level should be 90 percent.
b. We see that the whole confidence interval is within the set of negative numbers. Thus, we see that set $p_1$ yields a lower risk of polio, meaning that the claim should be accepted.
c. The p-value and critical value methods, which we learned in previous chapters, should be equal, while the newly-learned confidence interval method will be different.
