<< Chapter < Page Chapter >> Page >

Refer to the above problem. Suppose you randomly survey 11 California residents. We are interested in the number who have adequate earthquake supplies.

  • What is the probability that at least 8 have adequate earthquake supplies?
  • Is it more likely that none or that all of the residents surveyed will have adequate earthquake supplies? Why?
  • How many residents do you expect will have adequate earthquake supplies?
  • 0.0043
  • none
  • 3.3

The next 2 questions refer to the following: In one of its Spring catalogs, L.L. Bean® advertised footwear on 29 of its 192 catalog pages.

Suppose we randomly survey 20 pages. We are interested in the number of pages that advertise footwear. Each page may be picked at most once.

  • How many pages do you expect to advertise footwear on them?
  • Is it probable that all 20 will advertise footwear on them? Why or why not?
  • What is the probability that less than 10 will advertise footwear on them?

Suppose we randomly survey 20 pages. We are interested in the number of pages that advertise footwear. This time, each page may be picked more than once.

  • How many pages do you expect to advertise footwear on them?
  • Is it probable that all 20 will advertise footwear on them? Why or why not?
  • What is the probability that less than 10 will advertise footwear on them?
  • Reminder: A page may be picked more than once. We are interested in the number of pages that we must randomly survey until we find one that has footwear advertised on it. Define the random variable X and give its distribution.
  • What is the probability that you only need to survey at most 3 pages in order to find one that advertises footwear on it?
  • How many pages do you expect to need to survey in order to find one that advertises footwear?

  • 3.02
  • No
  • 0.9997
  • 0.3881
  • 6.6207 pages

Suppose that you roll a fair die until each face has appeared at least once. It does not matter in what order the numbers appear. Find the expected number of rolls you must make until each face has appeared at least once.

Try these multiple choice problems.

For the next three problems : The probability that the San Jose Sharks will win any given game is 0.3694 based on a 13 year win history of 382 wins out of 1034 games played (as of a certain date). An upcoming monthly schedule contains 12 games.
Let X size 12{X} {} = the number of games won in that upcoming month.

The expected number of wins for that upcoming month is:

  • 1.67
  • 12
  • 382 1043
  • 4.43

D: 4.43

What is the probability that the San Jose Sharks win 6 games in that upcoming month?

  • 0.1476
  • 0.2336
  • 0.7664
  • 0.8903

A: 0.1476

What is the probability that the San Jose Sharks win at least 5 games in that upcoming month

  • 0.3694
  • 0.5266
  • 0.4734
  • 0.2305

C: 0.4734

For the next two questions : The average number of times per week that Mrs. Plum’s cats wake her up at night because they want to play is 10. We are interested in the number of times her cats wake her up each week.

In words, the random variable X size 12{X} {} =

  • The number of times Mrs. Plum’s cats wake her up each week
  • The number of times Mrs. Plum’s cats wake her up each hour
  • The number of times Mrs. Plum’s cats wake her up each night
  • The number of times Mrs. Plum’s cats wake her up

A: The number of times Mrs. Plum's cats wake her up each week

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Collaborative statistics (custom lecture version modified by t. short). OpenStax CNX. Jul 15, 2013 Download for free at http://cnx.org/content/col11543/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Collaborative statistics (custom lecture version modified by t. short)' conversation and receive update notifications?

Ask