Exam 4: Probability and Probability Distributions

If A and B are any two events with P(A) = .8 and P(B| ) = .7, then P( and B) is

What is the probability that a respondent chosen at random enjoys shopping for clothing?

When two events are independent, they are also mutually exclusive.

Two events A and B are said to mutually be exclusive if P(A and B) = 0.

The law of large numbers states that subjective probabilities can be estimated based on the long run relative frequencies of events.

A small grocery store is considering installing an express checkout line. Let X be the number of customers in the regular checkout line. Note that these numbers include the customers being served, if any. The probability distribution of X is given in the table below. -Find the probability that at least two people are in line.

Calculate the variance of the probability distribution.

What is the probability that this project will not be completed on time?

The possible annual percentage return of the stocks of Gamma, Inc. and Delta, Inc. share a common probability distribution, given below. -(A) What is the expected annual return of each stock? (B) What is the standard deviation of the annual return of each stock? (C) On the basis of your answers to (A) and (B), which of these stocks would you prefer to buy? Defend your choice. (D) Are the annual returns of these two stocks positively or negatively associated with each other? How might the answer to this question influence your decision to purchase shares?

How many of the wells can the company expect to be successful?

The formal way to revise probabilities based on new information is to use:

If A and B are independent events with P(A) = 0.40 and P(B) = 0.50, then P(A/B) is 0.50.

The law of large numbers is relevant to the estimation of:

What is the standard deviation of the probability distribution?