Question

求概率论题目

做出题目最多者悬赏

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Answer 1

1.
0.15*0.02+0.8*0.01+0.05*0.03=0.0125

2.
E(X)=-2/5-1/6+1/15+11/10
=(-24-10+4+66)/60
=36/60
=0.6
E(X^2)=4/5+1/6+1/15+99/30
=(48+10+4+198)/60
=26/6
=13/3
D(X)=E(X^2)-E(X)^2=13/3-0.36=11.92/3=3.97

E(3X+2)=3E(X)+2=3.8

3.
Z -1 0 1 2

P 1/4 1/3 1/6 1/4

X 0 1

P 1/4+1/6=5/12 7/12

Y -1 0 1
P 1/4+1/6=5/12 1/6+1/6=1/3 1/4

4.
1)Kx^3/3|(x 0~1）=1
K/3=1
K=3

2) ∫(0.2~1)3x^2 dx
=1-0.2^3

=0.992

3)F(x)=x^3 (0<x<1)

4)E(X)=∫(0~1) 3x^3 dx
=(3x^4)/4|(0~1)
=3/4
E(X^2)=∫(0~1) 3x^4 dx
=(3x^5)/5|(0~1)
=3/5
D(X)= E(X^2)-E(X)^2=3/5-9/16=3/90=1/30