Results 1 to 5 of 5

Math Help - URGENT Probability Question

  1. #1
    Newbie
    Joined
    Jul 2007
    Posts
    9

    URGENT Probability Question

    End
    Last edited by badboychow; July 12th 2007 at 09:31 AM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Jul 2007
    Posts
    90
    When you say "he gets 2 sixes" you mean "he gets exactly 2 sixes?"
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jul 2007
    Posts
    9
    End
    Last edited by badboychow; July 12th 2007 at 09:29 AM.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,866
    Thanks
    745
    Hello, badboychow!

    You're doing great!


    A man rolls a die for 10 times. .Find the probability that:
    1. he gets two 6's
    2. he gets five even numbers and five odd numbers
    3. he gets at least two 5's
    4. he gets three 3's and three 1's
    5. he gets two 6's, given that he gets two 5's
    6. he doesn't get the same number consecutively

    My answers are:
    1. 0.2907. . .Yes!
    2. 0.24609 . Correct!
    3. 0.51548 . Right!

    4. Three 3's and three 1's
    We want three 3's, three 1's, and four Others.

    . . {10\choose3,3,4}\left(\frac{1}{6}\right)^3\left(\f  rac{1}{6}\right)^3\left(\frac{4}{6}\right)^4 \;=\;0.017781842



    5. Two 6's, given that he gets two 5's.
    Bayes' Theorem: . P(\text{two 6's }|\text{ two 5's}) \;=\;\frac{P(\text{two 6's and two 5's})}{P(\text{two 5's})}

    Numerator: P(\text{two 6's and two 5's}) \:=\:{10\choose2,2,6}\left(\frac{1}{6}\right)^2\le  ft(\frac{1}{6}\right)^2\left(\frac{4}{6}\right)^6\  ;=\;0.085352843

    Denominator: P(\text{two 5's}) \;=\;{10\choose2}\left(\frac{1}{6}\right)^2\left(\  frac{5}{6}\right)^8 \;=\;0.290710049

    Therefore: . P(\text{two 6's }|\text{ two 5's}) \;=\;\frac{0.085352842}{0.290710049} \;=\;0.293601282



    6. He doesn't get the same number consecutively.
    The first (#1) can be any number: . \frac{6}{6} \:=\:1

    The next (#2) must not match #1: . \frac{5}{6}

    The next (#3) must not match #2: . \frac{5}{6}

    The next (#4) must not match #3: . \frac{5}{6}

    . . . and so on . . .

    The last (#10) must not match #9: . \frac{5}{6}


    Answer: . 1 \times \left(\frac{5}{6}\right)^9 \;=\;0.193806699

    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Jul 2007
    Posts
    9
    End
    Last edited by badboychow; July 12th 2007 at 09:30 AM.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Help Probability Question Urgent
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: February 14th 2009, 09:12 PM
  2. Probability Question [URGENT!!!]
    Posted in the Statistics Forum
    Replies: 1
    Last Post: September 25th 2008, 03:29 AM
  3. **urgent: Desperate Probability Question**
    Posted in the Statistics Forum
    Replies: 2
    Last Post: June 3rd 2008, 07:31 PM
  4. urgent question on probability and statictics
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: April 14th 2008, 04:53 PM
  5. urgent probability question
    Posted in the Statistics Forum
    Replies: 2
    Last Post: January 6th 2008, 06:48 PM

Search Tags


/mathhelpforum @mathhelpforum