Results 1 to 2 of 2

Math Help - Normal distribution

  1. #1
    Member
    Joined
    Apr 2013
    From
    Mahinog
    Posts
    81
    Thanks
    5

    Normal distribution

    The weight of 1000 students in a secondary school has a normal distribution with a mean of 68.5kg and a standard deviation of 2.7kg. assume that the weight has been round up into one decimal place, how many students will be expected to have weight equal to 69.0kg?

    I've tried P(68.9<X< 69.1) , and got 29
    but the answer is 72
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Sep 2012
    From
    Australia
    Posts
    3,607
    Thanks
    591

    Re: Normal distribution

    Hey Trefoil2727.

    Using R I got the same answer you got:

    > (pnorm(69.1,68.5,2.7)-pnorm(68.9,68.5,2.7))*1000
    [1] 29.04248

    Theoretically of course, the probability of getting exactly something in a continuous distribution is 0.

    Are there any other assumptions that have been used?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: March 23rd 2013, 04:35 PM
  2. Replies: 1
    Last Post: March 21st 2013, 02:59 AM
  3. normal distribution prior and posterior distribution proof
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: March 9th 2011, 06:12 PM
  4. Replies: 2
    Last Post: March 29th 2010, 02:05 PM
  5. Replies: 1
    Last Post: April 20th 2008, 06:35 PM

Search Tags


/mathhelpforum @mathhelpforum