1. A GP estimates that about 50% of her patients have 'trivial' problems. What is the probability that four out of fi ve patients in one evening's surgery have trivial problems?

2. Suppose a hospital Accident and Emergency department has an average of 10 new emergency cases per hour. Calculate the probability of observing exactly 10 new emergency cases in any given hour.

3. The systolic blood pressure of 16 middle age men before exercise has a Normal distribution with a mean of 141.1 mmHg and a standard deviation of 13.62 mmHg. What is the probability having a systolic blood pressure of 160 mmHg or higher?