Normal Random Variables Question

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SUMMARY

The discussion centers on solving problems related to normal random variables, specifically Y ~ N(300, 100) and H ~ N(4000, 25). The probability Pr(300 < Y < 320) is calculated as 0.4772. Additionally, the transformation of H into a random variable R using the function R = f(H) = 0.5H – 60 results in an expected value E(R) of 1940 and a variance Var(R) of 156.25. The user expresses confusion regarding the calculations and seeks clarification on the correctness of the provided answers.

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Homework Statement



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) = 156.25I 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
 
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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)
 
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?
 

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