3.A vaccine is 95 percent effective. What is the probability that it is not effective for:

(a) One and only one individual out of 20 individuals? (b) More than one out of 20 individuals?
2025-04-14 14:21:05
推荐回答(1个)
回答1:

一种疫苗的有效率是95%, 那么它没有效的可能性是:
a) 20个人中只有一个人?
b) 20个人中多过一个人?
答案应该是a, 因为对5%的人可能无效