设连续型随机变量x在区间【3,5】上服从均匀分布,其密度函数为 ;P(2<X<4)= ;E(X)= ;D(X)=

如题所述

P(2<X<4) =P(3<X<4) =(4-3)/(5-2) = 1/3
E(X) = (3+5)/2 = 4
E(X^2) = (1/2)∫(3->5) x^2 dx =(1/6)[ x^3]|(3->5)= 49/3
D(X)=E(X^2) -[E(X)]^2 =49/3-16=1/3
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