cancel
Showing results for 
Search instead for 
Did you mean: 

Hypergeometric Distribution Formula

Super User
293 Views
Super User
Super User

Hypergeometric Distribution Formula

As explained here: https://www.statisticshowto.datasciencecentral.com/hypergeometric-distribution-examples/

 

The hypergeometric distribution is a probability distribution that’s very similar to the binomial distribution. In fact, the binomial distribution is a very good approximation of the hypergeometric distribution as long as you are sampling 5% or less of the population.


Therefore, in order to understand the hypergeometric distribution, you should be very familiar with the binomial distribution. Plus, you should be fairly comfortable with the combinations formula.

 

combinations.png

Hypergeometric Distribution Formula

The (somewhat formal) definition for the hypergeometric distribution, where X is a random variable, is:

hypergeometric-distribution-formula.png

 

This Quick Measure does the calculation above and has a bunch of error checking to boot.

 

 

 

Probability = 
VAR __error = IF(ISBLANK(K[K Value]) || ISBLANK('k 2'[k Value 2]) || ISBLANK(N[N Value]) || ISBLANK([n Value 2]) || [n Value 2]<'k 2'[k Value 2] || K[K Value]<'k 2'[k Value 2] || N[N Value]<'n 2'[n Value 2] || N[N Value]<K[K Value],TRUE(),FALSE())
VAR __numerator = IF(__error,1,COMBIN(K[K Value],'k 2'[k Value 2])*COMBIN(N[N Value]-K[K Value],'n 2'[n Value 2]-'k 2'[k Value 2]))
VAR __demoninator = IF(__error,1,COMBIN(N[N Value],'n 2'[n Value 2]))
RETURN
IF(__error,"Bad Parameters",DIVIDE(__numerator,__demoninator,0))

 

 


Did I answer your question? Mark my post as a solution!

Proud to be a Datanaut!