Results 1 to 5 of 5

Math Help - Help with Probability

  1. #1
    Junior Member
    Joined
    Jun 2009
    Posts
    28

    Help with Probability

    Need some help to solve this one. Don't understand how I should start and so ...



    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 kevin3000 View Post
    Need some help to solve this one. Don't understand how I should start and so ...



    Have you been taught Markov Chains? If not, then you can draw a tree diagram:

    Note that Monday is dry so the first two branches are dry (0.8) and rainy (0.2). Now draw the next set of branches and use the given information to label their probability.

    Now use the tree diagram to get the answer. I get (0.8)(0.2) + (0.2)(0.6) = .... but you better double check because I'm terrible at these things.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Jun 2009
    Posts
    28
    Quote Originally Posted by mr fantastic View Post
    Have you been taught Markov Chains? If not, then you can draw a tree diagram:

    Note that Monday is dry so the first two branches are dry (0.8) and rainy (0.2). Now draw the next set of branches and use the given information to label their probability.

    Now use the tree diagram to get the answer. I get (0.8)(0.2) + (0.2)(0.6) = .... but you better double check because I'm terrible at these things.
    I don't understand 100% can someone further explain
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Dec 2009
    From
    toronto
    Posts
    17
    Quote Originally Posted by kevin3000 View Post
    I don't understand 100% can someone further explain
    As there are only 2 days, it's probably easier to list all possibilities
    Let p denote the probability of dry/rainy
    Mon Dry: p=1

    Tue Dry: p=0.8
    Wed Dry: p=0.8*0.8
    Wed Rainy: p=0.8*0.2

    Tue Rainy: p=0.2
    Wed Dry: p=0.2*0.4
    Wed Rainy: p=0.2*0.6

    hence simply add up all the probabilities that makes Wed a rainy day
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by kevin3000 View Post
    I don't understand 100% can someone further explain
    It would help if you said which part of the 100% you didn't understand. Are you saying that you don't know what a tree diagram is?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 10
    Last Post: January 21st 2011, 12:47 PM
  2. Replies: 3
    Last Post: May 29th 2010, 08:29 AM
  3. Joint Probability/Marginal Probability
    Posted in the Statistics Forum
    Replies: 0
    Last Post: March 2nd 2010, 11:15 PM
  4. Replies: 1
    Last Post: February 18th 2010, 02:54 AM
  5. Replies: 3
    Last Post: December 15th 2009, 07:30 AM

Search Tags


/mathhelpforum @mathhelpforum