一道排列组合 概率题8个人成绩,数学由低到高60,65,70,75,80,85,90,95,物理由低到高72,77,80,84,88,90,93,95,设8人中,两科成绩均不低于90分的人数为X,求分布列,和期望值.
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/14 01:41:40
![一道排列组合 概率题8个人成绩,数学由低到高60,65,70,75,80,85,90,95,物理由低到高72,77,80,84,88,90,93,95,设8人中,两科成绩均不低于90分的人数为X,求分布列,和期望值.](/uploads/image/z/1102393-1-3.jpg?t=%E4%B8%80%E9%81%93%E6%8E%92%E5%88%97%E7%BB%84%E5%90%88+%E6%A6%82%E7%8E%87%E9%A2%988%E4%B8%AA%E4%BA%BA%E6%88%90%E7%BB%A9%2C%E6%95%B0%E5%AD%A6%E7%94%B1%E4%BD%8E%E5%88%B0%E9%AB%9860%2C65%2C70%2C75%2C80%2C85%2C90%2C95%2C%E7%89%A9%E7%90%86%E7%94%B1%E4%BD%8E%E5%88%B0%E9%AB%9872%2C77%2C80%2C84%2C88%2C90%2C93%2C95%2C%E8%AE%BE8%E4%BA%BA%E4%B8%AD%2C%E4%B8%A4%E7%A7%91%E6%88%90%E7%BB%A9%E5%9D%87%E4%B8%8D%E4%BD%8E%E4%BA%8E90%E5%88%86%E7%9A%84%E4%BA%BA%E6%95%B0%E4%B8%BAX%2C%E6%B1%82%E5%88%86%E5%B8%83%E5%88%97%2C%E5%92%8C%E6%9C%9F%E6%9C%9B%E5%80%BC.)
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