18 Last year, at Northern Manufacturing Company, 200 people had colds during the year. One hundred fifty-five people who did no exercising had colds, whereas the remainder of the people with colds were involved in a weekly exercise program. Half of the 1,000 employees were involved in some type of exercise.

(a) What is the probability that an employee will have a cold next year?

(b) Given that an employee is involved in an exercise program, what is the probability that he or she will get a cold?

(c) What is the probability that an employee who is not involved in an exercise program will get a cold next year?

(d) Are exercising and getting a cold independent events? Explain your answer.