In a beach, 35% of people are males, and 60% of males and 75% of females are wearing sunglasses.
(a) If a person is chosen from the beach randomly, find the probability that the person is wearing sunglasses.
(b) Given that a person is wearing sunglasses, find the probability that the person is a male. (Give your answer correct to 3 sig. fig.)
*唔該詳解
F.5 math-probability(2)
2011-02-27 8:07 pm
回答 (1)
2011-02-27 8:21 pm
✔ 最佳答案
(a) P(wearing sunglasses)= P(wearing sunglasses|male)P(male) + P(wearing sunglasses|female)P(female)
= (0.6)(0.35) + (0.75)(0.65)
= 0.6975
(b) By Bayes theorem,
P(male|wearing sunglasses)
= P(wearing sunglasses|male)P(male)/P(wearing sunglasses)
= (0.6)(0.35)/0.6975
= 0.301 (correct to 3 sig. fig.)
收錄日期: 2021-04-13 17:50:39
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110227000051KK00411