[商管] 統計學-西葛馬問題

[NiceKitty (想要有個依靠><)]

不好意思再請教各位大大一題><

Consider n independent trials,each of which results in any of the

outcomes i, i=1,2,3 with respective probabilities P1,p2,p3

 3
ΣPi=1.Let Ni denote the number of trials that result in outcome i,
i=1

and show that Cov(N1,N2).

Also explain why it is intuitive that this covariance is negative.



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推 locust0923:用三項分配去解就好了