A company buys equal quantities of pens from A and B, the company random draws and tests 2 pens from each lot that A and B provide. It accepts the lot if both pens are good. Quality of pens are independent of each other. If 3% and 2% of pens from A and B respectively are bad, find
(a) Probability of accepting only one lot by the company.
(b) Probability that the only accepted lot is from A. (Ans. 0.3963)
Probability
2010-07-11 10:15 pm
回答 (1)
2010-07-11 10:29 pm
✔ 最佳答案
a)P(accepting only one lot by the company)
= P(accepting A only) + P(accepting B only)
= P(both pens of A are good and at least one pen of B is bad) +
P(both pens of B are good and at least one pen of A is bad)
= [(1 - 3%)^2][1 - (1 - 2%)^2] + [(1 - 2%)^2][1 - (1 - 3%)^2]
= (0.97^2)(1 - 0.98^2) + (0.98^2)(1 - 0.97^2)
= 0.09402
b)
P(the only accepted lot is from A)
= P(accepting A only) / [ P(accepting A only) + P(accepting B only) ]
= (0.97^2)(1 - 0.98^2) / 0.09402
= 0.3963
收錄日期: 2021-04-21 22:11:54
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100711000051KK00731