The probability that a patient recovers from a delicate heart operation is 0.9. Of the next 100 patients having this operation, what is the probability that
a. between 84 and 95 inclusive survive?
b. fewer than 86 survive?
Math 問題 probability HELP ME>O<
2012-10-25 2:50 am
回答 (1)
2012-10-25 5:30 am
✔ 最佳答案
(a) Using normal distribution to approximate binomial distributionE(X) = 100 * 0.9 = 90
Var(X) = 100 * 0.9 * 0.1 = 9
So, P(between 84 and 95 inclusive survive)
= P(83.5 <= X <= 95.5) (notice correction factor)
= P[(83.5 - 90)/3 <= Z <= (95.5 - 90)/3]
P(-2.1667 <= Z <= 1.8333)
= 0.9514
(b) P(fewer than 86 survive)
P(X < 85.5)
= P[Z < (85.5 - 90)/3]
= P(Z < -1.5)
= 0.0668
收錄日期: 2021-04-26 19:18:58
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20121024000051KK00414