如果题目中不列明是小于还是小于等于6，是默认按小于不包含来做吗

问题如下：

In a discrete uniform distribution with 20 potential outcomes of integers 1 to 20, the probability that X is greater than or equal to 3 but less than 6, P(3 ≤ X < 6), is:

选项：

A.

0.10

B.

0.15

C.

0.20

解释：

B is correct.

The probability of any outcome is 0.05, P(1) = 1/20 = 0.05. The probability that X is greater than or equal to 3 but less than 6, which is expressed as P(3 ≤ X < 6) = P(3) + P(4) + P(5) = 0.05 + 0.05 + 0.05 = 0.15

本题目的在于从1到20个数字里抽数，问抽出一个数字，且这个数字在3到6这个区间里的概率是多少。

抽出一个数字3的概率就是1/20，抽出数字4的概率就是1/20，抽出一个数字5的概率就是1/2。

所以以把所有的可能性都加起来就是 P(3) + P(4) + P(5) = 0.05 + 0.05 + 0.05 = 0.15