已知隨機變數X~B(6,1/3),那麼V(X)等於多少?

已知隨機變數X~B(6,1/3),那麼V(X)等於多少?


隨機變數X~B(6,1/3),
則n=6,p=1/3,q=2/3,
那麼V(X)=npq=4/3



2(x+1)等於6 4(x-1)等於1-x 3-(1+2x)等於-2 3(2x-1)-2(1-x)
2(x+1)等於6
4(x-1)等於1-x
3-(1+2x)等於-2
3(2x-1)-2(1-x)=0


2 1 2 1/8



[1+(2x-4)/(x+1)(x-2)]÷[x+3/x2-1]其中x等於6


[1+(2x-4)/(x+1)(x-2)]÷[x+3/x²;-1]
=[1+2/(x+1)]×(x²;-1)/(x+3)
=(x+3)/(x+1)×(x+1)(x-1)/(x+3)
=x-1
=6-1
=5