Suppose we randomly sample 100 individuals and find that their mean number of doctor visits per year is 10, with a standard deviation of 10. Suppose we want to test whether the mean number of doctor visits is 9 among the population.

a. What is the null hypothesis? What is the alternative hypothesis?

b. Estimate the t-test statistic for this hypothesis test. Can we reject the null hypothesis at a significance level = 0.1? Why or why not?

c. Can we reject the null hypothesis at a significance level = 0.05? Why or why not?