Negative Binomial Or Pascal Distribution

Question 1

The negative binomial is used for ?

Formula for negative binomial

Answer 1

• it is used to model the number of trials before the given number of successes
• It is used to describe the distribution of discrete data the distribution will become aggregated or contagious
• To measure contagious discrete events p

Pdf f(x)=x-1Cr-1 P^r (1-p)^n-r
Mean= r/p
Variance =rq/p =r(1-p) /p

Question 2

Poisson approximation to binomial distribution

Answer 2

To identify Poisson p will be small then n will be very large