Results 1 to 2 of 2

Math Help - Probability with a die and with coins.

  1. #1
    Newbie
    Joined
    Oct 2009
    From
    UAE
    Posts
    2

    Exclamation Probability with a die and with coins.

    Hello Everyone
    How r u doing?


    hmmm this is my homework, I've solved part of it but i faced some difficulties with the rest Qs.
    so could some1 please help me


    Prob. 1:
    Let A and B be two events. Prove the following:
    *P(A intercept B)>= P(A)+P(B)-1
    *P(AUnion b)>=P(A)
    Prob. 2:
    A die is loaded in such a way that the probability of each face turning up is proportional to the number of dots on that face. (For example, a six is three times as probable as a two.) . The die is thrown once.
    • What is the probability of getting 1?
    • What is the probability of getting an odd number?
    Prob. 3:
    You have 2 coins, a fair one with P(H) = ½, and an unfair one with P(H) = 1/3. A coin is selected at random and tossed, falling heads up. How likely that it is the fair one?


    Many thanx
    Last edited by mr fantastic; October 14th 2009 at 06:49 PM. Reason: Changed post itle
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by my.life View Post
    Hello Everyone
    How r u doing?


    hmmm this is my homework, I've solved part of it but i faced some difficulties with the rest Qs.
    so could some1 please help me


    Prob. 1:
    Let A and B be two events. Prove the following:
    *P(A intercept B)>= P(A)+P(B)-1
    *P(AUnion b)>=P(A)
    Prob. 2:

    A die is loaded in such a way that the probability of each face turning up is proportional to the number of dots on that face. (For example, a six is three times as probable as a two.) . The die is thrown once.

    • What is the probability of getting 1?
    • What is the probability of getting an odd number?
    Prob. 3:
    You have 2 coins, a fair one with P(H) = ½, and an unfair one with P(H) = 1/3. A coin is selected at random and tossed, falling heads up. How likely that it is the fair one?


    Many thanx
    1) Draw a Venn diagram to assist in the proof.


    2) Write out the probability distribution table:

    Pr(X = 1) = k
    Pr(X = 2) = 2k
    Pr(X = 3) = 3k
    .
    .
    .
    Pr(X = 6) = 6k.

    1 = k + 2k + 3k + .... + 6k => k =

    Now that you know the probabilities you can answer the questions.


    3) Start by drawing a tree diagram. Can you do this?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Coins Probability
    Posted in the Algebra Forum
    Replies: 5
    Last Post: July 9th 2010, 02:05 AM
  2. Coins Probability
    Posted in the Statistics Forum
    Replies: 4
    Last Post: February 10th 2010, 09:07 PM
  3. the jury, probability and coins
    Posted in the Statistics Forum
    Replies: 3
    Last Post: September 17th 2009, 01:44 PM
  4. Probability of Coins toss....
    Posted in the Statistics Forum
    Replies: 5
    Last Post: April 1st 2009, 10:18 PM
  5. Probability - Coins
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: January 16th 2007, 12:57 PM

Search Tags


/mathhelpforum @mathhelpforum