<< Chapter < Page Chapter >> Page >

Refer to the information in [link] . P = tests positive.

  1. Given that a woman develops breast cancer, what is the probability that she tests positive. Find P ( P | B ) = 1 - P ( N | B ).
  2. What is the probability that a woman develops breast cancer and tests positive. Find P ( B AND P ) = P ( P | B ) P ( B ).
  3. What is the probability that a woman does not develop breast cancer. Find P ( B′ ) = 1 - P ( B ).
  4. What is the probability that a woman tests positive for breast cancer. Find P ( P ) = 1 - P ( N ).

a. 0.98; b. 0.1401; c. 0.857; d. 0.15

Got questions? Get instant answers now!
Got questions? Get instant answers now!

Try it

A student goes to the library. Let events B = the student checks out a book and D = the student checks out a DVD. Suppose that P ( B ) = 0.40, P ( D ) = 0.30 and P ( D | B ) = 0.5.

  1. Find P ( B′ ).
  2. Find P ( D AND B ).
  3. Find P ( B | D ).
  4. Find P ( D AND B′ ).
  5. Find P ( D | B′ ).
  1. P ( B′ ) = 0.60
  2. P ( D AND B ) = P ( D | B ) P ( B ) = 0.20
  3. P ( B | D ) = P ( B  AND  D ) P ( D ) = ( 0.20 ) (0 .30) = 0.66
  4. P ( D AND B′ ) = P ( D ) - P ( D AND B ) = 0.30 - 0.20 = 0.10
  5. P ( D | B′ ) = P ( D AND B′ ) P ( B′ ) = ( P ( D ) - P ( D AND B ))(0.60) = (0.10)(0.60) = 0.06
Got questions? Get instant answers now!

References

DiCamillo, Mark, Mervin Field. “The File Poll.” Field Research Corporation. Available online at http://www.field.com/fieldpollonline/subscribers/Rls2443.pdf (accessed May 2, 2013).

Rider, David, “Ford support plummeting, poll suggests,” The Star, September 14, 2011. Available online at http://www.thestar.com/news/gta/2011/09/14/ford_support_plummeting_poll_suggests.html (accessed May 2, 2013).

“Mayor’s Approval Down.” News Release by Forum Research Inc. Available online at http://www.forumresearch.com/forms/News Archives/News Releases/74209_TO_Issues_-_Mayoral_Approval_%28Forum_Research%29%2820130320%29.pdf (accessed May 2, 2013).

“Roulette.” Wikipedia. Available online at http://en.wikipedia.org/wiki/Roulette (accessed May 2, 2013).

Shin, Hyon B., Robert A. Kominski. “Language Use in the United States: 2007.” United States Census Bureau. Available online at http://www.census.gov/hhes/socdemo/language/data/acs/ACS-12.pdf (accessed May 2, 2013).

Data from the Baseball-Almanac, 2013. Available online at www.baseball-almanac.com (accessed May 2, 2013).

Data from U.S. Census Bureau.

Data from the Wall Street Journal.

Data from The Roper Center: Public Opinion Archives at the University of Connecticut. Available online at http://www.ropercenter.uconn.edu/ (accessed May 2, 2013).

Data from Field Research Corporation. Available online at www.field.com/fieldpollonline (accessed May 2,2 013).

Chapter review

The multiplication rule and the addition rule are used for computing the probability of A and B , as well as the probability of A or B for two given events A , B defined on the sample space. In sampling with replacement each member of a population is replaced after it is picked, so that member has the possibility of being chosen more than once, and the events are considered to be independent. In sampling without replacement, each member of a population may be chosen only once, and the events are considered to be not independent. The events A and B are mutually exclusive events when they do not have any outcomes in common.

Formula review

The multiplication rule: P ( A AND B ) = P ( A | B ) P ( B )

The addition rule: P ( A OR B ) = P ( A ) + P ( B ) - P ( A AND B )

Use the following information to answer the next ten exercises. Forty-eight percent of all Californians registered voters prefer life in prison without parole over the death penalty for a person convicted of first degree murder. Among Latino California registered voters, 55% prefer life in prison without parole over the death penalty for a person convicted of first degree murder. 37.6% of all Californians are Latino.

In this problem, let:

  • C = Californians (registered voters) preferring life in prison without parole over the death penalty for a person convicted of first degree murder.
  • L = Latino Californians

Suppose that one Californian is randomly selected.

In words, what is C | L ?

C | L means, given the person chosen is a Latino Californian, the person is a registered voter who prefers life in prison without parole for a person convicted of first degree murder.

Got questions? Get instant answers now!

In words, what is L AND C ?

L AND C is the event that the person chosen is a Latino California registered voter who prefers life without parole over the death penalty for a person convicted of first degree murder.

Got questions? Get instant answers now!

Are L and C independent events? Show why or why not.

Got questions? Get instant answers now!

Find P ( L OR C ).

0.6492

Got questions? Get instant answers now!

In words, what is L OR C ?

Got questions? Get instant answers now!

Are L and C mutually exclusive events? Show why or why not.

No, because P ( L AND C ) does not equal 0.

Got questions? Get instant answers now!

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Introductory statistics. OpenStax CNX. May 06, 2016 Download for free at http://legacy.cnx.org/content/col11562/1.18
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Introductory statistics' conversation and receive update notifications?

Ask