单选题 设相互独立的两随机变量X，Y均服从E(1)分布，则P{1＜min(X，Y)≤2}的值为
  • A.e-1-e-2．
  • B.1-e-1．
  • C.1-e-2．
  • D.e-2-e-4．
【正确答案】 D
【答案解析】[解析] P{1＜min(X，Y)≤2}=P{min(X，Y)＞1}-P{min(X，Y)＞2}
=P{X＞1，Y＞1}-P{X＞2，Y＞2}
=P{X＞1}P{Y＞1}-P{X＞2}P{Y＞2}
=e-1·e-1-e-2e·e-2=e-2-e-4．