(1)P=1-(1/2)^4=15/16
(2)P(ξ=0)=(1/2)^2*(1-(1/2)^2)=3/16
P(ξ=1)=(1/2)^2*2*(1-(1/2)^2)=3/8
P(ξ=2)=(1/2)^2*(1-(1/2)^2)+(1/2)^2*(1/2)^2=1/4
P(ξ=3)=(1/2)^2*2*(1/2)^2=1/8
P(ξ=4)=(1/2)^4=1/16
如果有哪里不明白我再给你解释~
(1)P=1-(1/2)^4=15/16
(2)P(ξ=0)=(1/2)^2*(1-(1/2)^2)=3/16
P(ξ=1)=(1/2)^2*2*(1-(1/2)^2)=3/8
P(ξ=2)=(1/2)^2*(1-(1/2)^2)+(1/2)^2*(1/2)^2=1/4
P(ξ=3)=(1/2)^2*2*(1/2)^2=1/8
P(ξ=4)=(1/2)^4=1/16
如果有哪里不明白我再给你解释~