Exam 4: Introduction to Probability

A lottery is conducted using three urns. Each urn contains chips numbered from 0 to 9. One chip is selected at random from each urn. The total number of sample points in the sample space is

Assume that each year the IRS randomly audits 10% of the tax returns. If a married couple has filed separate returns, a. What is the probability that both the husband and the wife will be audited? b. What is the probability that only one of them will be audited? c. What is the probability that neither one of them will be audited? d. What is the probability that at least one of them will be audited?

Which of the following statements is always true?

Four workers at a fast food restaurant pack the take-out chicken dinners. John packs 45% of the dinners but fails to include a salt packet 4% of the time. Mary packs 25% of the dinners but omits the salt 2% of the time. Sue packs 30% of the dinners but fails to include the salt 3% of the time. You have purchased a dinner and there is no salt. a. Find the probability that John packed your dinner. b. Find the probability that Mary packed your dinner.

Ten individuals are candidates for positions of president, vice president of an organization. How many possibilities of selections exist?

The counting rule that is used for counting the number of experimental outcomes when n objects are selected from a set of N objects where order of selection is not important is called

Forty percent of the students who enroll in a statistics course go to the statistics laboratory on a regular basis. Past data indicates that 65% of those students who use the lab on a regular basis make a grade of A in the course. On the other hand, only 10% of students who do not go to the lab on a regular basis make a grade of A. If a particular student made an A, determine the probability that she or he used the lab on a regular basis.

When the results of experimentation or historical data are used to assign probability values, the method used to assign probabilities is referred to as the

An experiment consists of throwing two six-sided dice and observing the number of spots on the upper faces. Determine the probability that a. the sum of the spots is 3. b. each die shows four or more spots. c. the sum of the spots is not 3. d. neither a one nor a six appear on each die. e. a pair of sixes appear. f. the sum of the spots is 7.

In an experiment, events A and B are mutually exclusive. If PA) = 0.6, then the probability of B

If PA) = 0.50, PB) = 0.40, then, and PA ∪ B) = 0.88, then PB | A) =

A survey of business students who had taken the Graduate Management Admission Test GMAT) indicated that students who have spent at least five hours studying GMAT review guides have a probability of 0.85 of scoring above 400. Students who do not review have a probability of 0.65 of scoring above 400. It has been determined that 70% of the business students review for the test. a. Find the probability of scoring above 400. b. Find the probability that a student who scored above 400 reviewed for the test.

If a coin is tossed three times, the likelihood of obtaining three heads in a row is

If A and B are mutually exclusive events with PA) = 0.3 and PB) = 0.5, then PA ∩ B) =

Assume two events A and B are mutually exclusive and, furthermore, PA) = 0.2 and PB) = 0.4. a. Find PA ∩ B). b. Find PA ∪ B). c. Find PA | B).

The union of two events with nonzero probabilities

Two of the cylinders in an eight-cylinder car are defective and need to be replaced. If two cylinders are selected at random, what is the probability that a. both defective cylinders are selected? b. no defective cylinder is selected? c. at least one defective cylinder is selected?

A sample point refers to the