1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Normal Random Variables Question

  1. May 29, 2010 #1
    1. The problem statement, all variables and given/known data

    Problem 1 – Normal Random Variables

    B) Y ~ N(300, 100). Pr (300 < Y < 320) = 0.4772

    D) H ~ N(4000, 25). R = f(H) = 0.5H – 60. E(R) = 1940; Var(R) = 156.25





    I have a problem solving these problems above...I missed the class when we covered this subject and now I am lost upon solving them.. I hope somebody can help, thanks a lot
     
  2. jcsd
  3. May 30, 2010 #2

    statdad

    User Avatar
    Homework Helper

    For a normally distributed random variable,

    [tex]
    P(a < X < b) = P(X < b) - P(X < a)
    [/tex]

    For any random variable [itex] W [/itex], if [itex] a, b [/itex] are real numbers,
    and

    [tex]
    Z = aW + b
    [/tex]

    then

    [tex]
    E(Z) = aE(W) + b, \quad Var(Z) = a^2 Var(W)
    [/tex]

    (as long as the mean and variance of [itex] W [/itex] exist)
     
  4. May 31, 2010 #3
    Thanks for the reply!!

    However, when I plug it in I dnt get the right answer.... did u check if the given answer is right?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Normal Random Variables Question
  1. Normal Random Variable (Replies: 3)

Loading...