这个作业是计算骰子翻动的数学概率问题
CSE 21 HW 5
（1）假设您有两个6边公平的骰子。 您不断翻动骰子，直到
两个骰子中的最小值大于或等于5。您期望的次数是多少？
在停止之前必须掷骰子对吗？
（2）（a。）考虑拿两个公平的六面骰子，并独立滚动它们。 令X为绝对
这些掷骰结果的值（例如，如果掷4和6，则X的值为
| 4 − 6 | = 2）。 X的期望值和方差是多少？
（b。）考虑对正整数n独立滚动n个红色和n个蓝色的8边骰子。 让Y
是红色骰子结果的总和减去蓝色骰子的总和。 期望什么
Y的值和方差以n？
(3) Assume that we want to associate 5 digit ID numbers to memory positions labelled from 0 to 99.
We’ll do this by just taking the last two digits of the ID number. Assume that we randomly and
uniformally select 50 unique IDs of the possible 100,000 IDs.
(a.) What is the probability that we have no collisions (in other words that none of our 50 IDs end
with the same last two digits)? Your answer does not need to be simplified, but should be in a
closed form.
(b.) What is the expected number of collisions (in other words the number of pairs of our 50 IDs
that have the same last two digits)? Your answer does not need to be simplified, but should be
in a closed form.