对。如果加上以前选择，那就是条件概率，结果应该是一样

来源: 黄处长于 2009-02-07 13:18:15 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

WENXUECITY.COM does not represent or guarantee the truthfulness, accuracy, or reliability of any of communications posted by other users.