1 question about statistic
2011-10-21 7:17 am
19. Three quarters of the mortgage contracts approved by a bank have a mortgage period of 15 years or above, If 36 mortgagors are selected randomly and independently, find the probability that at least 30 of them have a mortgage period of 5 years or above. (correct to 4 decimal places.)
回答 (3)
2011-10-21 5:56 pm
✔ 最佳答案
Using Poisson distribution:λ = 36 x 0.75 = 27
So the required probability is:
e-27 x (2730/30! + 2731/31! + 2732/32! + 2733/33! + 2734/34! + 2735/35! + 2736/36!)
= 0.2677
參考: 原創答案
2011-10-22 2:59 am
It is a question from hkdse mathematics m1, a chapter called parameter estimation. And the answer is 0.1241
2011-10-22 2:00 am
Should be binomial distribution
2011-10-21 19:50:10 補充：
0.1241 is not a correct answer. Using binomial, exact answer is 0.1684. Using normal approximation, it is 0.1680. 0.1241 is using normal approximation also, but use x=29. 29.5 should be used instead.
2011-10-21 19:50:10 補充：
0.1241 is not a correct answer. Using binomial, exact answer is 0.1684. Using normal approximation, it is 0.1680. 0.1241 is using normal approximation also, but use x=29. 29.5 should be used instead.
收錄日期: 2021-04-23 23:25:35
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20111020000051KK00944