The proportion of people who live after suffering a stroke is 85%. Suppose you are studying a new treatment to increase survival rate after a stroke. You administer the new treatment to 100 randomly selected people who have recently had a stroke. You find a 95% survival rate in your sample. You perform a hypothesis test to determine the effectiveness of your new treatment with a significance level of 0.05.

a) State the null and alternate hypotheses using both words and symbols.

b) Is this a one-tailed or two-tailed test?

c) You calculate a z-statistic of 2.80. Find the p-value and interpret it in context.

d) Does the data indicate your treatment is effective? Why or why not?