Answer
a. The claim is supported.
b. The claim is supported.
c. Wearing a seat belt lowers fatality rate.
Work Step by Step
a. We want to see if the mean is different than $\frac{31}{2823}=.0110$, so we know $H_0: \mu = .0110$ and $H_1: \mu \lt .0110$. 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 0.0000, so the claim is supported.
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 is all positive, meaning that wearing a seat belt lowers fatality rate.
c. The results show that it does not have an impact on preventing dementia.
