掷到第一个 6：期望次数
Trials until First Success
题目详情
On the average, how many times must a die be thrown until one gets a 6?
解析
每次掷出 6 的概率为 ，等待次数服从几何分布，期望为
Trials until First Success
On the average, how many times must a die be thrown until one gets a 6?
每次掷出 6 的概率为 ，等待次数服从几何分布，期望为