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Probability - Random Variables

  1. Mar 7, 2012 #1
    1. The problem statement, all variables and given/known data

    1. A test consists of 10 true-false questions.
    (a) In how many ways can it be completed? (HINT: The task of completing the test consists
    of 10 stages. Use the Product Rule.)

    (b) A student answers the questions by
    flipping a coin. Let X denote the number of correctly
    answered questions.
    (i) The distribution of X is:

    binomial
    hypergeometric
    negative binomial
    Poisson

    (ii) Find the probability he/she will answer correctly at most 5 of the questions.





    2. Relevant equations / Attempt at a solution

    a) i believe this is just 210?

    b.) i.) is this binomial??

    ii.) [itex]\stackrel{n}{k}[/itex] * pk * (1-p)(n-k)

    p = 1/2
    k = 5
    n = 10

    [itex]\stackrel{n}{k}[/itex]
    is n choose k
     
  2. jcsd
  3. Mar 7, 2012 #2
    a)correct
    b)binomial
    binomcdf(10,.5,5)

    It's been awhile since I took statistics. There is a chance I'm wrong.
     
  4. Mar 7, 2012 #3

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    Your answers are correct.

    RGV
     
  5. Mar 8, 2012 #4
    So these statements are correct?

    p = 1/2
    k = 5
    n = 10

    I apologize, I am not familiar with the 'binomcdf(10,.5,5)' format
     
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