A law firm is deemed successful by the number of cases they win. A random sample of 16 law firms were asked to report the mean number of cases won. From previous studies we expect the mean to be 9.3 cases. Is there sufficient evidence to show the mean has decreased? Construct a 99% CI for the true average. Does the CI and hypothesis test agree? Explain.

11.5

7.5

8.3

8.9

9.1

6.6

7.9

6.9

10.1

9.6

9.9

10.2

8.5

5.6

7

8.2

What sample size would we use to get a margin of error less than 0.8?