Results 1 to 4 of 4
Like Tree2Thanks
  • 1 Post By romsek
  • 1 Post By pickslides

Thread: I do not even know where to start (Mean and Stndrd Deviation probability problem)

  1. #1
    Newbie
    Joined
    Jun 2014
    From
    Michigan
    Posts
    9

    I do not even know where to start (Mean and Stndrd Deviation probability problem)

    The maximum snow load expected on a roof during the life of a domed stadium is a normally distributed random variable with mean = 50 lb/ft^2 and standard deviation of 8 lb/ft^2. What is the probability that the snow load will exceed 60 lb/ft^2 at some time?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Nov 2013
    From
    California
    Posts
    4,547
    Thanks
    1865

    Re: I do not even know where to start (Mean and Stndrd Deviation probability problem)

    Quote Originally Posted by adubas View Post
    The maximum snow load expected on a roof during the life of a domed stadium is a normally distributed random variable with mean = 50 lb/ft^2 and standard deviation of 8 lb/ft^2. What is the probability that the snow load will exceed 60 lb/ft^2 at some time?
    this is about as straightforward a probability problem as there could be. If you don't even know where to start you need to pay more attention in class or to your textbook.

    Take your value, 60 lb/ft^2, normalize it according to the mean and deviation of your snow load distribution, 50 and 8 lb/ft^2, also known as finding it's z-score, and use the table of the CDF of the standard normal to find your probability.

    Note it will be 1 - Pr[snow load < 60 lb/ft^2].
    Thanks from topsquark
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,237
    Thanks
    33

    Re: I do not even know where to start (Mean and Stndrd Deviation probability problem)

    Transform to a Z score Z=\frac{X-\mu}{\sigma} = \frac{60-50}{8} = 1.25

    Now find P(Z>1.25)
    Thanks from topsquark
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Apr 2005
    Posts
    18,201
    Thanks
    2427

    Re: I do not even know where to start (Mean and Stndrd Deviation probability problem)

    There's a good app for the normal distribution at
    Standard Normal Distribution Table
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Probability and Standard deviation
    Posted in the Statistics Forum
    Replies: 1
    Last Post: Sep 18th 2012, 03:21 AM
  2. Replies: 4
    Last Post: Mar 23rd 2012, 04:18 AM
  3. Probability w/ standard deviation
    Posted in the Statistics Forum
    Replies: 1
    Last Post: Apr 12th 2011, 01:52 PM
  4. A question on Probability and deviation HELP!
    Posted in the Statistics Forum
    Replies: 2
    Last Post: Jan 12th 2009, 08:08 PM
  5. HELP! Where do I start with Probability?
    Posted in the Statistics Forum
    Replies: 4
    Last Post: Jun 20th 2008, 05:04 AM

Search Tags


/mathhelpforum @mathhelpforum