Results 1 to 5 of 5

Math Help - Discrete random variables

  1. #1
    Newbie
    Joined
    Oct 2010
    Posts
    16

    Discrete random variables

    124 students, 5 grills, sum of grills
    a. Findprobabilitydistributionforx.
    b.
    What is the probability that x exceeds 10?
    Last edited by noid; October 13th 2010 at 11:11 AM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor harish21's Avatar
    Joined
    Feb 2010
    From
    Dirty South
    Posts
    1,036
    Thanks
    10
    The prob distribution is wrong. P(x_{i})'s should sum up to 1

    Note that x represents the sum of the grill numbers selected by a student
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Oct 2010
    Posts
    16
    x1= 85
    x2= 124
    x3= 40
    x4= 12
    x5= 77

    Sum of all = 338

    Thus the probability for each is

    x1= 85 / 338
    x2= 124 / 338
    x3= 40 / 338
    x4= 12 / 338
    x5= 77 / 338

    This wouldnt this show the most likely choice is 1-2-5?

    and b) is 80% because only x4 doesnt have the probability to be atleast .10
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor harish21's Avatar
    Joined
    Feb 2010
    From
    Dirty South
    Posts
    1,036
    Thanks
    10
    well, as far as I can understand, x is the sum of the grill numbers. So x1=the sum of grill numbers is 1+2+3=6.
    and x2=sum of the grill numbers is (1+2+4=)7, x3= the sum of grill numbers is(1+2+5=)8, and so on...
    the sum of grill numbers exceeds 10 only in the last combination(2-4-5)
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Oct 2010
    Posts
    16
    Thats seems a bit to easy doesnt it? In that fashion you would disregard the size of the grill that the student selected?

    Because if there is 124 students and grill 1 (x1) gets chosen 85 times within all combinations picked. Grill 2 gets picked in all combinations, etc. Wouldnt that mean 338 grills are selected in total after all combinations are exhausted?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Discrete random variables (2)
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: October 11th 2010, 09:31 AM
  2. help with discrete random variables
    Posted in the Statistics Forum
    Replies: 7
    Last Post: October 2nd 2010, 09:55 PM
  3. Discrete Random Variables
    Posted in the Statistics Forum
    Replies: 4
    Last Post: April 13th 2010, 02:39 AM
  4. Replies: 3
    Last Post: January 13th 2010, 10:44 AM
  5. Discrete Random Variables
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: January 29th 2008, 10:48 PM

Search Tags


/mathhelpforum @mathhelpforum