If X be binomial distribution with mean np and variance npq, then find the`(P(x=k))/(P(x=k-1))`.

Options

A. `((n-k)/(k-1)).(p)/(q)`
B. `((n-k+1)/(k)).(p)/(q)`
C. `((n+1)/(k)).(q)/(p)`
D. `((n-1)/(k+1)).(q)/(p)`

Answer

B

Explanation

(b) `(P(X=k))/(P(Xk-1))=(""^(n)C_(k)p^(k)q^(n-k))/(""^(n)C_(k-1)p^(k-1+1))=((n-k+1)/(k)).(p)/(q)`