## Elementary Statistics (12th Edition)

a) We want to see if the mean is different to $\frac{277}{1524}=0.1818$, so we know $H_0:μ=0.1818$ and $H1:μ\lt0.1818$. We now use a Ti-84 calculator. To solve, go to "Stat," then "Tests," and then select "Stats." Doing this, we can find that the critical value and use a z-table calculator to find that $p\gt0.01$, so the claim is not supported. b) We use a ti-84 calculator 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 can find that the confidence interval goes through $0$, so the claim is not supported. c) The results show that it does not have an impact on preventing dementia.