Wednesday
March 22, 2017

Post a New Question

Posted by on Saturday, April 7, 2012 at 1:59pm.

An urn has fifteen red balls and nineteen white balls. Three balls are selected at random and the number of red balls are observed.

Find the probability distribution for
Number of Red Balls:
0 =
1 =
2 =
3 =

  • Probability Distribution - , Saturday, April 7, 2012 at 2:41pm

    total amount of balls = 15 red + 19 white = 34 balls

    0 - 0/34 = 0
    1 - 1/34
    2 - 2/34 = 1/17
    3 - 3/34

  • Probability Distribution - , Saturday, April 7, 2012 at 2:43pm

    Prob red = 15/34
    prob white = 19/34

    when picking three:
    prob(0 red) = C(3,0) (19/34)(18/33)(17/32) = 57/352
    prob(1 red) = C(3,1) (15/34)(19/33)(18/32) = 2565/5984
    prob(2red) = C(3,2) (15/34)(14/33)(19/32) = 1998/5984
    prob (3red) = C(3,3)(15/34)(14/33)(13/32) = 455/5984

    notice that the sum of the 4 fractions above is 5984/5984 = 1

  • typo - Probability Distribution - , Saturday, April 7, 2012 at 2:44pm

    the 2nd last prob calculation should be 1995/5984

Answer This Question

First Name:
School Subject:
Answer:

Related Questions

More Related Questions

Post a New Question