返回列表 发帖

Reading 9: Common Probability Distributions-LOS b 习题精选

Session 3: Quantitative Methods: Application
Reading 9: Common Probability Distributions

LOS b: Describe the set of possible outcomes of a specified discrete random variable.

 

 

Assume a discrete distribution for the number of possible sunny days in Provo, Utah during the week of April 20 through April 26. For this discrete distribution, p(x) = 0 when x cannot occur, or p(x) > 0 if it can. Based on this information, what is the probability of it being sunny on 5 days and on 10 days during the week, respectively?

A)
A positive value; infinite.
B)
A positive value; zero.
C)
Zero; infinite.


 

The probability of it being sunny on 5 days during the week has some positive value, but the probability of having sunshine 10 days within a week of 7 days is zero because this cannot occur.

Which of the following is least likely to be an example of a discrete random variable?

A)
The number of days of sunshine in the month of May 2006 in a particular city.
B)
Quoted stock prices on the NASDAQ.
C)
The rate of return on a real estate investment.


The rate of return on a real estate investment, or any other investment, is an example of a continuous random variable because the possible outcomes of rates of return are infinite (e.g., 10.0%, 10.01%, 10.001%, etc.). Both of the other choices are measurable (countable).

TOP

A random variable that has a countable number of possible values is called a:

A)
probability distribution.
B)
discrete random variable.
C)
continuous random variable.


A discrete random variable is one for which the number of possible outcomes are countable, and for each possible outcome, there is a measurable and positive probability. A continuous random variable is one for which the number of outcomes is not countable.

TOP

返回列表