Exam 2: Introduction to Probability

A mail order company tracks the number of returns it receives each day.Information for the last 50 days shows Number of returns Number of days 0-99 6 100-199 20 200-299 15 300 or more 9 a.How many sample points are there? b.List and assign probabilities to sample points. c.What procedure was used to assign these probabilities?

An automobile dealership is waiting to take delivery of nine new cars.Today,anywhere from zero to all nine cars might be delivered.It is appropriate to use the classical method to assign a probability of 1/10 to each of the possible numbers that could be delivered.

A method of assigning probabilities based upon judgment is referred to as the

In a recent survey in a Statistics class,it was determined that only 60% of the students attend class on Fridays.From past data it was noted that 98% of those who went to class on Fridays pass the course,while only 20% of those who did not go to class on Fridays passed the course. a. What percentage of students is expected to pass the course? b. Given that a person passes the course, what is the probability that he/she attended classes on Fridays?

Which of the following is not a proper sample space when all undergraduates at a university are considered?

If P(A)= 0.38,P(B)= 0.83,and P(A $\cap$ B)= 0.27; then P(A $U$ B)=

If A and B are independent events with P(A)= 0.1 and P(B)= 0.5,then P(A $U$ B)= .6.

Bayes' theorem provides a way to transform prior probabilities into posterior probabilities.

If P(A|B)= .4,then

A method of assigning probabilities that assumes the experimental outcomes are equally likely is referred to as the

Two events that are mutually exclusive cannot be independent.

A medical research project examined the relationship between a subject's weight and recovery time from a surgical procedure,as shown in the table below. Underweight Normal weight Overweight Less than 3 days 6 15 3 3 to 7 days 30 95 20 Over 7 days 14 40 27 a.Use relative frequency to develop a joint probability table to show the marginal probabilities. b.What is the probability a patient will recover in fewer than 3 days? c.Given that recovery takes over 7 days, what is the probability the patient is overweight?

A list of all possible outcomes of an experiment is called

Super Cola sales breakdown as 80% regular soda and 20% diet soda.While 60% of the regular soda is purchased by men,only 30% of the diet soda is purchased by men.If a woman purchases Super Cola,what is the probability that it is a diet soda?

P(A $\cap$ B)? P(A)

If P(A $\cap$ B)= 0

The probability of an event

It is estimated that 3% of the athletes competing in a large tournament are users of an illegal drug to enhance performance.The test for this drug is 90% accurate.What is the probability that an athlete who tests positive is actually a user?

In the set of all past due accounts,let the event A mean the account is between 31 and 60 days past due and the event B mean the account is that of a new customer.The complement of A is

Revised probabilities of events based on additional information are