| Exam Board | CAIE |
|---|
| Module | FP2 (Further Pure Mathematics 2) |
|---|
| Year | 2010 |
|---|
| Session | June |
|---|
| Topic | Hypothesis test of a normal distribution |
|---|
6 The amount of caffeine in a randomly selected cup of coffee dispensed by a machine has a normal distribution. The amount of caffeine in each of a random sample of 25 cups was measured. The sample mean was 110.4 mg and the unbiased estimate of the population variance was \(50.42 \mathrm { mg } ^ { 2 }\). Calculate a 90\% confidence interval for the mean amount of caffeine dispensed.