# Probability questions

31. Assume that we have two events, A and B, that are mutually exclusive. Assume further that we know P(A) = .30 and P(B) = .40

a. What is P(A B)?

b. What is P(A | B)?

c. A student in statistics argues that the concepts of mutually exclusive events and independent events are really the same, and that if events are mutually exclusively they must be independent. Do you agree with this statement? Use the probability information in this problem to justify your answer.

d. What general conclusion would you make about mutually exclusive and independent events given the results of this problem?

35. The US Bureau of Labor Statistics collected data on the occupations of workers 25 to

64 years old. The following table shows the number of male and female workers (in thousands) in each occupation category (Statistical Abstract of the United States:2002)

Occupation Male Female

Managerial/professional 19079 19021

Tech./Sales/Administrative 11079 19315

Service 4977 7947

Precision Production 11682 1138

Operators/Fabricators/Labor 10576 3482

Farming/Forestry/Fishing 1838 514

A. Develop a joint probability table.

B. What is the probability of a female worker being a manager or professional?

C. What is the probability of a male worker being in precision production?

D. Is occupation independent of gender? Justify your answer with a probability

Calculation.

37. A purchasing agent placed rush orders for a particular raw material with two different suppliers, A and B. If neither order arrives in four days, the production process must be shut down until at least one of the order arrives. The probability that supplier B can deliver the material in four days is .35

A. what is the probability that both suppliers will deliver the material in four days?

Because two separate suppliers are involved, we are willing to assume independence.

B. What is the probability that at least one supplier will deliver the material in four days.

C. What is the probability that the production process will be shut down in four days because of a shortage of raw material (i.e., both orders are lately)?

#### Solution Summary

Calculations of independence of events, probability, joint probability and conditional probability.