Probability
2008-03-12 2:52 pm
A large batch of resistors is known to contain 20% which are defective. If 5 resistors are drawn at random from the batch, calculate the probability that at least two of them are defective.
回答 (1)
2008-03-12 3:22 pm
✔ 最佳答案
P(defective) = 20% P(normal) = 1 – 20% = 80%
P(at least 2 are defective)
= 1 – P(less than two are defective)
= 1 – [P(no defective) + P(1 defective)]
= 1 – [(80%)5 + 5C1(80%)4(20%)]
= 0.2627
參考: Myself~~~
收錄日期: 2021-04-23 23:01:50
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080312000051KK00301