Results 1 to 3 of 3

Math Help - 2 Stupid Questions? Can anyone do these?

  1. #1
    Newbie
    Joined
    Mar 2008
    Posts
    19

    Post Probability Questions.. HELPP Can someone PLZ do these?

    Dr Harve has found that 30 % of his clients have eye problems, 10 have hearing and 5 have both.. are an (eye problem and hearing problems) independent or dependent? why


    T.O Leafs is playing Montreal in Stanley cup finals. team to win 4 first wins the cup. If the prob of T.O winning (1) game is .55 determine the prob that
    a) T.O wins 4 straight
    b) Montreal wins the cup ( In general)
    Last edited by wikji; March 4th 2008 at 03:54 AM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Junior Member roy_zhang's Avatar
    Joined
    Mar 2008
    Posts
    64
    Q.1
    First I guess you mean 10% and 5% instead of 10 and 5, am I right?
    If this is the case, we have P(E)=0.3, P(H)=0.1 and P(E\cap H)=0.05
    By definition, two events A and B are said to be independent if P(A\cap B)=P(A)P(B).
    But here we have P(E\cap H)=0.05 and P(E)P(H)=0.03, hence they are dependent.

    Q.2
    First part is easy, just P(wins 4 straight )=(0.55)^4\approx 0.0915;

    The second part deserves a little analysis, there are 4 cases a team can win the cup: (1) the team wins the 4th game in the 4th game in the series (this is the case of 4 straight wins as we found in part one); (2) the team wins the 4th game in the 5th game in the series; (3) the team wins the 4th game in the 6th game in the series;(4) the team wins the 4th game in the 7th game in the series. We need to sum all the four probabilities for these 4 cases, the second, third and fourth cases are follow exactly the negative binomial probability distribution (Check a reference for detail), so the probability for T.O. Leaf to win the series can be written as:

    P(W) = P(1) + P(2) + P(3) + P(4) where P(2) means the probability for case 2 above etc.

    P(W) = (0.55)^4 + \binom{4}{3}(0.55)^4(0.45)^1 + \binom{5}{3}(0.55)^4(0.45)^2 + \binom{6}{3}(0.55)^4(0.45)^3
     \approx 0.6083

    Thus the probability for Montreal to win will be 1-P(W)\approx 0.3917.
    Last edited by roy_zhang; March 5th 2008 at 09:45 AM.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Mar 2008
    Posts
    6
    Quote Originally Posted by wikji View Post
    Dr Harve has found that 30 % of his clients have eye problems, 10 have hearing and 5 have both.. are an (eye problem and hearing
    T.O Leafs is playing Montreal in Stanley cup finals. team to win 4 first wins the cup. If the prob of T.O winning (1) game is .55 determine the prob that
    a) T.O wins 4 straight
    b) Montreal wins the cup ( In general)
    independant u don't c with ears and hear with eyes
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. am i being stupid?
    Posted in the Algebra Forum
    Replies: 2
    Last Post: June 26th 2008, 05:46 AM
  2. Probably very easy but i'm stupid
    Posted in the Algebra Forum
    Replies: 3
    Last Post: March 26th 2008, 06:18 AM
  3. stupid me
    Posted in the Algebra Forum
    Replies: 9
    Last Post: September 5th 2006, 07:42 PM
  4. stupid probability
    Posted in the Statistics Forum
    Replies: 6
    Last Post: May 11th 2006, 01:45 PM

Search Tags


/mathhelpforum @mathhelpforum