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X1, X2 and X3 are three independent random variables. Xi ~ N (4, 12), for i=1, 2, 3.?
E(Y) = Standard Deviation(Y) =
Update:
Y= (X1 +X2 + X3)/3
1 Answer
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- GuillermoLv 79 years agoFavorite Answer
X1 ∼ n(4; 12)...............X2 ∼ n(4; 12)............X3 ∼ n(4; 12)
μx1 = 4........................μx2 = 4.....................μx3 = 4
σ1^2 = 144....................σ2^2 = 144.................σ3^2 = 144
Y = (X1 +X2 + X3)/3
E(Y) = (4 + 4 + 4)/3 = 4
μy = 4
V(Y) = ((V(X1) + V(X2) + V(X3))/3^2 = 3*V(X1)/3^2 = 144/3
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