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分步乘法计数原理

> 已知盘中有编号为A,B,C,D的4个红球,4个黄球,4个白球(共 12个球)现从中摸出4个球(除编号与颜色外球没有区别) （12分）（1）求掐好包含字母A, B,C,D的概率; （2）设摸出的4个球中出现的颜色种数为随机变量X.求X的分布列和期望E(X).

问题：

发布时间：2024-09-10

已知盘中有编号为A,B,C,D的4个红球,4个黄球,4个白球(共 12个球)现从中摸出4个球(除编号与颜色外球没有区别) （12分）
（1）求掐好包含字母A, B,C,D的概率;
（2）设摸出的4个球中出现的颜色种数为随机变量X.求X的分布列和期望E(X).

参考答案：

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已知盘中有编号为A,B,C,D的4个红球,4个黄球,4个白球(共 12个球)现从中摸出4个球(除编号与颜色外球没有区别) （12分） （1）求掐好包含字母A, B,C,D的概率; （2）设摸出的4个球中出现的颜色种数为随机变量X.求X的分布列和期望E(X).

可能感兴趣的题目：

已知盘中有编号为A,B,C,D的4个红球,4个黄球,4个白球(共 12个球)现从中摸出4个球(除编号与颜色外球没有区别) （12分）
（1）求掐好包含字母A, B,C,D的概率;
（2）设摸出的4个球中出现的颜色种数为随机变量X.求X的分布列和期望E(X).