Question

已知X的概率密度函数为f(x)=1/2x (0

Answer 1

∫(0~1) (1/2)x dx

=1/4

2)

E(x)=∫(0~2) 0.5x²dx

= 8/6

=4/3

E(x²)=∫(0~2) 0.5x³ dx

= 16/8

=2

D(x)=2-16/9=2/9