Connecting...

This is a quick preview of the lesson. For full access, please Log In or Sign up.
For more information, please see full course syllabus of Probability
For more information, please see full course syllabus of Probability
Probability Hypergeometric Distribution
Lecture Description
In this lesson, we are going to be discussing the glamorously named hypergeometric distribution. First you'll see the situation where you would use the hypergeometric distribution. Then you'll learn the definition: the hypergeometric distribution describes choosing a committee of n men and women from a larger group of r women and N-r men. This is an unordered choice, without replacement. There are a lot of parameters in the formula for this distribution, and once you understand them, it'll be easier for you to memorize the formula. We are also going to go over some key properties of the hypergeometric distribution.
Bookmark & Share
Embed
Share this knowledge with your friends!
Copy & Paste this embed code into your website’s HTML
Please ensure that your website editor is in text mode when you paste the code.(In Wordpress, the mode button is on the top right corner.)
×
Since this lesson is not free, only the preview will appear on your website.
- - Allow users to view the embedded video in full-size.
3 answers
Tue Sep 2, 2014 7:57 PM
Post by David Llewellyn on August 28, 2014
I don't follow where you get each indicator variable to be equal to r/N.
Y1 is OK but, surely, the probability of picking the gender of the second person depends on your first choice as there is no replacement. If the first choice is a woman then the probability of getting a woman on the second choice is (r-1)/(N-1) but if the first choice was a man then the probability of getting a woman is r/(N-1).
The probability of picking a woman gets even more complex on the third choice as it depends on whether you have picked 2, 1 or 0 women already being (r-2)/(N-2), (r-1)/(N-2) and r/(N-2) respectively.
This trend continues all the way up to the nth choice where depending on how many women have been picked already the probability of picking a woman is (r-n-1)/(N-n-1), ... (r-2)/(N-n-1), (r-1)/(N-n-1), r/(N-n-1).
I can't see how this simplifies to nr/N.
What am I missing?