Results 1 to 2 of 2

Math Help - Binomial Distribution

  1. #1
    Junior Member
    Joined
    Aug 2009
    Posts
    69

    Binomial Distribution

    Alex has 5 shots at a dart board. He knows the probability of getting a bullseye is 0.6.

    a) Find the probability that

    i) No bullseye is hit. I get P(X=0) = ^4C_0\times (0.6)^0(0.4)^5

    ii) At least one bulleyes is hit. I get P(X\geq 1) = 1-^4C_0\times (0.6)^0(0.4)^5

    Here's where the confusion sets in.

    b) Find the number of throws required such that the probability of at least one bullseye being thrown is at least 0.7

    I know I have to make something >0.7.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Mar 2008
    Posts
    934
    Thanks
    33
    Awards
    1
    Quote Originally Posted by Bushy View Post
    Alex has 5 shots at a dart board. He knows the probability of getting a bullseye is 0.6.

    a) Find the probability that

    i) No bullseye is hit. I get P(X=0) = ^4C_0\times (0.6)^0(0.4)^5

    ii) At least one bulleyes is hit. I get P(X\geq 1) = 1-^4C_0\times (0.6)^0(0.4)^5

    Here's where the confusion sets in.

    b) Find the number of throws required such that the probability of at least one bullseye being thrown is at least 0.7

    I know I have to make something >0.7.
    Just rework part ii for n throws instead of 5, then find the least n such that the probability is at least 0.7.

    You should have ^5C_0 in your formulas instead of ^4C_0, but it won't make any difference in the final result.

    You are implicitly assuming that the chances of hitting on different throws are independent. It would be good to state that assumption explicitly.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Binomial Distribution
    Posted in the Statistics Forum
    Replies: 6
    Last Post: November 18th 2011, 12:48 PM
  2. Replies: 3
    Last Post: March 21st 2010, 05:25 PM
  3. Replies: 1
    Last Post: November 12th 2009, 12:38 AM
  4. Replies: 1
    Last Post: March 11th 2009, 11:09 PM
  5. Cumulative distribution function of binomial distribution
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: October 31st 2008, 03:34 PM

Search Tags


/mathhelpforum @mathhelpforum