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Find the Mean and Variance of Random Variable Z = (5x+3)

  1. Mar 2, 2012 #1
    1. The problem statement, all variables and given/known data
    Find the Mean and Variance of Random Variable Z = (5x+3)

    Using data set: AwPGYl.jpg


    Using:
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    &
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    3. The attempt at a solution
     
    Last edited: Mar 2, 2012
  2. jcsd
  3. Mar 2, 2012 #2
    Sorry the data set it so large, i've been trying to adjust it to no avail.


    EDIT: Fixed it, should be easier to view now
     
    Last edited: Mar 2, 2012
  4. Mar 2, 2012 #3

    Ray Vickson

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    You have a very small table of x and f(x) values. What is stopping you from computing EX? Why don't you just compute EX, then use that value in the computation of Var(X) = sum f(x)*(x-EX)^2 ?

    RGV
     
  5. Mar 3, 2012 #4
    They want us to use the theorem and corollary, any ideas? i'm not too savvy with this stuff yet.
     
  6. Mar 3, 2012 #5

    Ray Vickson

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    OK, so use the theorem and the corollary. Does the first theorem have E(X) in it? Do you know the value of E(X)? If not, you need to compute it. Does the second theorem have [itex] \text{Var}(X) = \sigma_x^2[/itex] in it? Do you know the value of Var(X)? If not, you need to compute it.

    RGV
     
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