Answer
a. The claim is valid.
b. The claim is valid.
c. Men and women have similar success rates.
Work Step by Step
a. We want to see if the mean is less than $\frac{421}{1412}=.2982$, so we know $H_0: \mu = .2982$ and $H_1: \mu \ne .2982$. We now use a Ti-84 calculator. To solve, go to "Stat," then "Tests," and then select "Stats." Doing this, we find that the critical value and use a z-table calculator to find that p is more than .05, so the claim is valid.
b. We use a ti-84 to find the confidence interval. To do this, we press “Stat” and then select “Tests.” Next, we select “2-PropZInt” to conduct the test. Doing this, we find that the confidence interval goes through 0, so the claim is valid.
c. The results show that men and women do have similar success rates when challenging calls.
