Normal Random Variables Question


by Onetimeuser
Tags: normal, random, variables
Onetimeuser
Onetimeuser is offline
#1
May29-10, 10:58 PM
P: 2
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
Phys.Org News Partner Science news on Phys.org
Lemurs match scent of a friend to sound of her voice
Repeated self-healing now possible in composite materials
'Heartbleed' fix may slow Web performance
statdad
statdad is offline
#2
May30-10, 09:12 AM
HW Helper
P: 1,344
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)
Onetimeuser
Onetimeuser is offline
#3
May31-10, 11:34 AM
P: 2
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?


Register to reply

Related Discussions
normal random variables (2nd) Calculus & Beyond Homework 2
normal random variables (3rd) Calculus & Beyond Homework 2
normal random variables Calculus & Beyond Homework 2
Proof required: Sum of squared standard normal random variables is a Chi-square rv Set Theory, Logic, Probability, Statistics 1
Probability inequality for the sum of independent normal random variables Set Theory, Logic, Probability, Statistics 3