A random sample of 500 people born in 1981 is being studied. It can be assumed that
birthdays are uniformly distributed throughout the year. Use the Poisson distribution to
find the probabilities that there are
(a) exactly two people, and
(b) no more than two people, with birthdays on 1st January.
probablilty?
2015-11-19 10:15 am
回答 (1)
2015-11-19 12:49 pm
✔ 最佳答案
λ = 500*(1/365) = 100/73P(x) = λ^x * e^(-λ) / x ! = (100/73)^x * e^(-100/73) / x !
(a)
P(2)
= (100/73)^2 * e^(-100/73) / 2 !
≒ 0.238 ..... Ans
(b)
P( x ≦ 2 )
P(0) + P(1) + P(2)
= (100/73)^0*e^(-100/73)/0! + (100/73)^1*e^(-100/73)/1! + (100/73)^2*e^(-100/73)/2!
≒ 0.841 ..... Ans
收錄日期: 2021-05-02 14:08:42
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20151119021557AABpH7O