Question

设随机变量X～B(5,p),且E(X)=0.5,求D(X)?如题 谢谢了

Answer 1

E(X)=np=0.5,p=05/n=0.5/5=0.1 D(X)=np(1-p)=5×0.1×﹙1－0.1﹚=0.45