设E(X)=-1，D(X)=4，由切比雪夫不等式估计概率P{-4＜X＜2}≥_____．

设E(X)=-1，D(X)=4，由切比雪夫不等式估计概率P{-4＜X＜2}≥_____．
【正确答案】：5/9 P{-4＜X＜2}=P{-3＜X-E(X)＜3}=P{{X-E(X)|＜3}≥1-D(X)/9=1-4/9=5/9