Results 1 to 4 of 4

Math Help - Not making sense...probability

  1. #1
    Newbie
    Joined
    Oct 2008
    Posts
    2

    Not making sense...probability

    30% of calls to an airline reservation phone line result in a reservation being made.
    a. Suppose that an operator handles 10 calls. What is the probability that none of the 10 calls results in a reservaion?
    b. What assumption did you make in order to calculate the probability in part (a)
    c. What is the probability that at least one call results in a reservation being made?

    This probably won't be my last question. I'm not understanding statistics much and I've never been great shakes at maths. Thanks!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
    Quote Originally Posted by Evergreen View Post
    30% of calls to an airline reservation phone line result in a reservation being made.
    a. Suppose that an operator handles 10 calls. What is the probability that none of the 10 calls results in a reservaion?
    b. What assumption did you make in order to calculate the probability in part (a)
    c. What is the probability that at least one call results in a reservation being made?

    This probably won't be my last question. I'm not understanding statistics much and I've never been great shakes at maths. Thanks!

    Looks Binomial to me.

    when X is Bi(n=no of trials,p=probabilty of success)
    Use P(X=x) = nCx p^x(1-p)^n-x

    with:
    p (prob of reservation being made) = .30
    n = 10

    a. P(X=10) = 10C10(.3)^10(1-.3)^10-10

    b. each call was independant of the next.

    c. P(X>=1) = P(X=1)+P(X=2)+P(X=3)+....+P(X=10)
    = 1-P(X=0)
    = 10C0(.3)^0(1-.3)^10-0
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by pickslides View Post
    Looks Binomial to me.

    when X is Bi(n=no of trials,p=probabilty of success)
    Use P(X=x) = nCx p^x(1-p)^n-x

    with:
    p (prob of reservation being made) = .30
    n = 10

    a. P(X=10) = 10C10(.3)^10(1-.3)^10-10

    b. each call was independant of the next.

    c. P(X>=1) = P(X=1)+P(X=2)+P(X=3)+....+P(X=10)
    = 1-P(X=0)
    = 10C0(.3)^0(1-.3)^10-0
    I agree. Except that part (a) requires Pr(X = 0), not Pr(X = 10).
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
    Quote Originally Posted by mr fantastic View Post
    I agree. Except that part (a) requires Pr(X = 0), not Pr(X = 10).
    Yep, I did not see the "none" part in part a)

    P(X=0) it is.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: December 1st 2011, 12:08 PM
  2. Replies: 3
    Last Post: November 21st 2011, 11:43 PM
  3. the probability of making a type II error CALCULATE BETA
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: February 25th 2010, 04:18 PM
  4. Replies: 8
    Last Post: February 10th 2009, 04:19 PM
  5. Geo HW not AT ALL making sense
    Posted in the Geometry Forum
    Replies: 7
    Last Post: December 7th 2008, 07:18 PM

Search Tags


/mathhelpforum @mathhelpforum