For a hypergeometric random variable, determine

P{X=k+1}/P{X=k}

Short Answer

Expert verified

(K-k)(n-k)(k+1)(N-K-n+k+1)

Step by step solution

01

Given information

For Hypergeometric random variable with parameters N,K,nwe have that

P(X=k)=Kk·N-Kn-kNn

02

Calculation

So we have that

P(X=k+1)P(X=k)=Kk+1·N-Kn-(k+1)NnKk·N-Kn-kNn=Kk+1·N-Kn-(k+1)Kk·N-Kn-k

03

Continue Calculation

When we write out these binomial coefficients, we get that the expression above is equal to

K!(k+1)!(K-k-1)!·(N-K)!(n-k-1)!(N-K-n+k+1)!K!k!(K-k)!·(N-K)!(n-k)!(N-K-n+k)!

04

Final answer

If we cancel out everything we can we left with.

(K-k)(n-k)(k+1)(N-K-n+k+1)

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Most popular questions from this chapter

Five distinct numbers are randomly distributed to players numbered1through 5. Whenever two players compare their numbers, the one with the higher one is declared the winner. Initially, players1and 2 compare their numbers; the winner then compares her number with that of player 3, and so on. Let X denote the number of times player 1 is a winner. FindPX=i,i=0,1,2,3,4.

If the distribution function of Xis given by

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