1. Serum cholesterol were taken from a population of college students. The results were normally distributed. Males had a mean of 195 and a standard deviation of 10. Female a had a mean of 185 and a standard deviation of 12. Concern was expressed by the health educators on a particular college campus of 10,000 that students with serum cholesterol levels above 200 might be at an increased risk of heart disease. If the campus was equally divided between males and females, what are the probabilities of males and females on this campus would be at risk?

2. The weight of 18-24 year old women are normally distributed with a mean of 132 pounds and a standard deviation of 27.4 .If one randomly selected 150 of these selected women age 18-24 years, how many of them would be expected to weigh 100 to 150 pounds?

3. An athletic association wants to sponsor a footrace. The average time it takes to run the course is 586 mins. with a standard deviation of 4.3 mins. If the association decides to include only the top 20% of the racer, what should the cut off time be the tryout run?

4. Assume that the age at onset of disease X is distributed normally with a mean of 50 years and a standard deviation of 12 years. What is the probability that an individual afflicted with disease X developed it before age 35?