標題: [Core] [十萬火急] Probability 題目一問 [打印本頁]

---

作者: Methodical    時間: 2016-9-21 03:50 PM     標題: [十萬火急] Probability 題目一問

a)
Concrete blocks are tested and it is found that, on average, 7% fail to meet the required specification. To pick up 9 concrete blocks from a batch of concrete blocks in a construction site, determine the probabilities that less than three blocks out from the chosen 9 concrete blocks will fail to meet the specification.


Let N = no. of concrete blocks that fail from a batch of 9 concrete blocks


P (less than 3 blocks fail)
= P(N=0) + P(N=1) + P(N=2)
= (1-0.07)^9 + (9C1) (1-0.07)^(8) (0.07) + (9C2) (1-0.07)^7(0.07)^2
=0.9791


咁樣岩唔岩？ thanks a lot!

[ 本帖最後由 Methodical 於 2016-9-21 03:58 PM 編輯 ]

---

作者: ken812    時間: 2016-9-21 10:33 PM

the answer is correct. Just rmb to specify what distribution are you using in order to get M marks even if your answer is wrong.

***N ~ B( 9, 0.07) ***

---

歡迎光臨 小卒資訊論壇 (http://lsforum.net/board/)

Powered by Discuz! 6.0.0