设随机变量X~b(3,0.4),求Y=X^2-2X的分布律
问题描述：
设随机变量X~b(3,0.4),求Y=X^2-2X的分布律
答
P(X=0)=0.6^3=0.216,此时Y=0P(X=1)=3*0.4*0.6^2=0.432,此时Y=-1P(X=2)=3*0.4^2*0.6=0.288,此时Y=0P(X=3)=0.4^3=0.064,此时Y=3上述概率可转化为：P(Y=0)=0.504P(Y=-1)=0.432P(Y=3)=0.064故其分布为y 0 -1 3P 0.504 0....