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Homework Statement
Find the variance of Y=3x^2+3x+3
The Attempt at a Solution
Let Y = 3x^2 +3x +3
Var(Y) = Var(3x^2 +3x +3) = 9Var(x^2) +9Var(x) = 9 [E[X^4] - E[X^2]^2 +E[X^2] - E[X]^2]
This is wrong.
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I guess the z should be X, or 9var(x) should be 9Var(Z). Either way, what assumption does that step require?Var(3x^2 +3z +1) = 9Var(x^2) +9Var(x)
I guess the z should be X, or 9var(x) should be 9Var(Z). Either way, what assumption does that step require?
Homework Statement
Find the variance of Y=3x^2+3x+3
The Attempt at a Solution
Let Y = 3x^2 +3x +3
Var(Y) = Var(3x^2 +3x +3) = 9Var(x^2) +9Var(x) = 9 [E[X^4] - E[X^2]^2 +E[X^2] - E[X]^2]
This is wrong.