A box contains 700 blue and 300 red balls. 200 balls are randomly chosen at the same time, & X is the number of red balls chosen.
A) List the possible values that the random variable X can have.
B) Find the probability mass function of X.
C) Find E[X].
D) Find Var(X).
E) What's the probability that exactly 50 of the balls chosen are red?
Math Help Please?
2018-07-18 6:02 am
回答 (2)
2018-07-18 7:17 am
✔ 最佳答案
a/X={0,1,...,200}
b/
Hypergeometric distribution
Pr(X=x) = C(300 , x)*C(700,200-x)/C(1000 , 200)
c/
E(X)=(300/(700+300))*200=60
d/
plug in formula ---> Var(X)=33.63= ...calculator
e/
C(300,50)*(C(700,150)/C(1000,200)
2018-07-18 6:05 am
I hope you get an F on this assessment.
收錄日期: 2021-04-24 01:06:21
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20180717220256AAXk1Gf