But they're accountable and we can list all possible values when they're discrete and form a probability weighted average of the outcomes.

但随机变量是离散的话,我们可以把所有的可能值列出来,然后算出加权平均值

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That's different when you have continuous values-- you don't have P because it's always zero.

和离散型随机变量的分布不同的是,连续型随机变量的分布中,某一点的概率值始终是零

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