business stats chapter 4

34. If events A and B are mutually exclusive, calculate P(A|B). A. Can't be determined B. 0 C. 1 D. 0.50

B. 0

26. At a college, 70 percent of the students are women and 50 percent of the students receive a grade of C. 25 percent of the students are neither female nor C students. Use this contingency table. C *C Women .45 .25 .70 Men .05 .25 .30 .50 .50 1.00 What is the probability that a student is female and a C student? A. .45 B. .50 C. .70 D. .25 E. .05

A. .45

31. Two percent (2%) of the customers of a store buy cigars. Half of the customers who buy cigars buy beer. 25 percent who buy beer buy cigars. Determine the probability that a customer buys beer. A. 0.25 B. 0.01 C. 0.04 D. 0.50 E. 0.005

C. 0.04

22. What is the probability of at least one tail in the toss of three fair coins? A. 1/8 B. 4/8 C. 5/8 D. 7/8 E. 6/8

D. 7/8

35. If P(A|B) = .2 and P(B) = .8, determine the intersection of event A and B. A. 0.20 B. 1.0 C. 0.25 D. 0.16 E. 0.60

D. 0.16

23. A machine is made up of 3 components: an upper part, a mid part, and a lower part. The machine is then assembled. 5 percent of the upper parts are defective; 4 percent of the mid parts are defective; 1 percent of the lower parts are defective. What is the probability that a machine is non-defective? A. 0.100 B. 0.903 C. 0.900 D. 0.0002 E. 0.912

B. 0.903 (.95) (.96) (.99) = .9029

12. If events A and B are independent, then P(A|B) is equal to _____. A. P(B) B. P(A n B) C. P(A) D. P(A U B)

C. P(A)

17. The _______ of two events A and B is another event that consists of the sample space outcomes belonging to either event A or event B or both event A and B. A. Union B. Intersection C. Complement D. Mutually exclusivity

A. Union

21. What is the probability that an even number appears on the toss of a die? A. 0.5 B. 0.33 C. 0.25 D. 0.67 E. 1.00

A. 0.5

9. A(n) _____ is the set of all of the distinct possible outcomes of an experiment. A. Sample Space B. Union C. Intersection D. Observation

A. Sample Space

36. In a report on high school graduation, it was stated that 85% of high school students graduate. Suppose 3 high school students are randomly selected from different schools. What is the probability that all graduate? A. 0.85 B. 0.947 C. 0.614 D. 0.283 E. 0.003

C. 0.614

25. What is the probability of winning four games in a row, if the probability of winning each game individually is 1/2? A. 1/4 B. 1/8 C. 1/2 D. 3/16 E. 1/16

E. 1/16 (1/2)(1/2)(1/2)(1/2)=1/6

42. In the word BUSINESS, what is the probability of randomly selecting the letter S? A. 2/8 B. 1/8 C. 3/8 D. 5/8

C. 3/8

38. In a report on high school graduation, it was stated that 85% of high school students graduate. Suppose 3 high school students are randomly selected from different schools. What is the probability that none graduate? A. 0.019 B. 0.003 C. 0.614 D. 0.057 E. 0.150

B. 0.003

43. Suppose that you believe that the probability you will get a grade of B or better in Introduction to Finance is .6, and the probability that you will get a grade of B or better in Introduction to Accounting is .5. If these events are independent, what is the probability that you will get a grade of B or better in both courses? A. 0.300 B. 0.833 C. 0.600 D. 0.500 E. 0.800

A. 0.300

11. When the probability of one event is not influenced by whether or not another event occurs, the events are said to be _____. A. Independent B. Dependent C. Mutually exclusive D. Experimental

A. Independent

5. The set of all possible experimental outcomes is called a(n): A. Sample space B. Event C. Experiment D. Probability

A. Sample space

29. At a college, 70 percent of the students are women and 50 percent of the students receive a grade of C. 25 percent of the students are neither female nor C students. Use this contingency table. C *C Women .45 .25 .70 Men .05 .25 .30 .50 .50 1.00 If the student has received a grade of C, what is the probability that he is male? A. 0.05 B. 0.10 C. 0.30 D. 0.17 E. 0.50

B. 0.10

16. The __________ of event X consists of all sample space outcomes that do not correspond to the occurrence of event X. A. Independence B. Complement C. Conditional probability D. Dependence

B. Complement

33. If A and B are independent events, P(A) = .2, and P(B) = .7, determine P(A U B) A. 0.90 B. 0.14 C. 0.76 D. 0.50 E. 0.24

C. 0.76

20. What is the probability of rolling a value higher than eight with a pair of fair dice? A. 6/36 B. 18/36 C. 10/36 D. 8/36 E. 12/36

C. 10/36

4. If two events are independent, we can _____ their probabilities to determine the intersection probability. A. Divide B. Add C. Multiply D. Subtract

C. Multiply

2. ___________________ is a measure of the chance that an uncertain event will occur. A. Random experiment B. Sample Space C. Probability D. A complement E. A population

C. Probability

28. At a college, 70 percent of the students are women and 50 percent of the students receive a grade of C. 25 percent of the students are neither female nor C students. Use this contingency table. C *C Women .45 .25 .70 Men .05 .25 .30 .50 .50 1.00 If the student is male, what is the probability he is a C student? A. 0.05 B. 0.10 C. 0.30 D. 0.17 E. 0.50

D. 0.17

45. Suppose that A1, A2 and B are events where A1 and A2 are mutually exclusive events and P(A1) = .7 P(A2) = .3 P(B│A1) = .2 P(B│A2) = .4 Find P(A1│B) A. 0.12 B. 0.26 C. 0.21 D. 0.54 E. 0.28

D. 0.54

24. A family has two children. What is the probability that both are girls, given that at least one is a girl? A. 1/8 B. 1/4 C. 1/2 D. 1/3 E. 1/6

D. 1/3

3. In which of the following are the two events A and B, always independent? A. A and B are mutually exclusive. B. The probability of event A is not influenced by the probability of event B. C. The intersection of A and B is zero. D. P(A|B) = P(A). E. B and D.

E. B and D.

6. A ____________ is the probability that one event will occur given that we know that another event already has occurred. A. Sample space outcome B. Subjective Probability C. Complement of events D. Long-run relative frequency E. Conditional probability

E. Conditional probability

44. Suppose that A1 , A2 and B are events where A1 and A2 are mutually exclusive events and P(A1) = .7 P(A2) = .3 P(B│A1) = .2 P(B│A2) = .4 Find P(B) A. 0.60 B. 0.26 C. 0.21 D. 0.14 E. 0.28

B. 0.26

30. At a college, 70 percent of the students are women and 50 percent of the students receive a grade of C. 25 percent of the students are neither female nor C students. Use this contingency table. C *C Women .45 .25 .70 Men .05 .25 .30 .50 .50 1.00 If the student has received a grade of C, what is the probability that she is female? A. 0.45 B. 0.90 C. 0.70 D. 0.64 E. 0.50

B. 0.90

32. Two percent (2%) of the customers of a store buy cigars. Half of the customers who buy cigars buy beer. 25 percent who buy beer buy cigars. Determine the probability that a customer neither buys beer nor buys cigars. A. 0.98 B. 0.95 C. 0.75 D. 0.96 E. 0.50

B. 0.95

10. The _____ of an event is a number that measures the likelihood that an event will occur when an experiment is carried out. A. Outcome B. Probability C. Intersection D. Observation

B. Probability

27. At a college, 70 percent of the students are women and 50 percent of the students receive a grade of C. 25 percent of the students are neither female nor C students. Use this contingency table. C *C Women .45 .25 .70 Men .05 .25 .30 .50 .50 1.00 What is the probability that a student is male and not a C student? A. .45 B. .50 C. .70 D. .25 E. .05

D. .25

37. In a report on high school graduation, it was stated that 85% of high school students graduate. Suppose 3 high school students are randomly selected from different schools. What is the probability that exactly one of the three graduates? A. 0.019 B. 0.003 C. 0.614 D. 0.057 E. 0.850

D. 0.057

39. In a local survey, 100 citizens indicated their opinions on a revision to a local land use plan. Of the 62 favorable responses, there were 40 males. Of the 38 unfavorable responses, there were 15 males. If one citizen is randomly selected find the probability A female or has an unfavorable opinion. A. 0.83 B. 0.17 C. 0.51 D. 0.60 E. 0.61

D. 0.60

13. A(n) _______________ probability is a probability assessment that is based on experience, intuitive judgment, or expertise. A. Experimental B. Relative frequency C. Objective D. Subjective

D. Subjective

41. In a local survey, 100 citizens indicated their opinions on a revision to a local land use plan. Of the 62 favorable responses, there were 40 males. Of the 38 unfavorable responses, there were 15 males. If one citizen is randomly selected find the probability (s)he has a favorable opinion or has an unfavorable opinion A. 0.00 B. 1.00 C. 0.62 D. 0.24

B. 1.00

14. A(n) ______________ is a collection of sample space outcomes. A. Experiment B. Event C. Set D. Probability

B. Event

18. The _______ of two events A and B is the event that consists of the sample space outcomes belonging to both event A and event B. A. Union B. Intersection C. Complement D. Mutually exclusivity

B. Intersection

7. The _______ of two events X and Y is another event that consists of the sample space outcomes belonging to either event X or event Y or both event X and Y. A. Complement B. Union C. Intersection D. Conditional probability

B. Union

8. P(AUB) = P(A) + P(B) - P(A n B) represents the formula for the A. conditional probability B. addition rule C. addition rule for two mutually exclusive events D. multiplication rule

B. addition rule

40. In a local survey, 100 citizens indicated their opinions on a revision to a local land use plan. Of the 62 favorable responses, there were 40 males. Of the 38 unfavorable responses, there were 15 males. If one citizen is randomly selected find the probability A male and has a favorable opinion A. 0.40 B. 0.65 C. 0.62 D. 0.55 E. 0.25

A. 0.40

15. Probabilities must be assigned to experimental outcomes so that the probabilities of all the experimental outcomes must add up to ___. A. 1 B. between 0 and 1 C. between -1 and 1 D. 0

A. 1

19. What is the probability of rolling a seven with a pair of fair dice? A. 6/36 B. 3/36 C. 1/36 D. 8/36 E. 7/36

A. 6/36

1. Two mutually exclusive events having positive probabilities are ______________ dependent. A. Always B. Sometimes C. Never

A. Always