wajzc
幼苗
共回答了22个问题采纳率:77.3% 举报
X和Y是独立的吧.
因为泊松分部的变量只能是X=0,1,2.,Y=0,1,2.
所以P(X>=0)=P(Y>=0)=1
P{min(X,Y)=0}
=P{X=0,Y>=0}+P(Y=0,X>=0}=P(X=0)P(Y>=0)+P(Y=0)P(X>=0)-P(x=0)P(y=0)
=P(X=0)*1+P(Y=0)*1-P(x=0)P(y=0)
=(1^0)e^(-1)/0!+(2^0)e^(-2)/0!-[(1^0)e^(-1)/0!]*[(2^0)e^(-2)/0!]
=(1/e)+(1/e^2)-(1/e)*(1/e^2)
=(1/e)+(1/e^2)-(1/e^3)
1年前
5