Monday, January 23, 2012

Is It Your Birthday? You are Not Alone!

Here’s a birthday paradox for you! If there are 23 people in a room, there’s a tad more chance than 50% that at least two of them will have the same birthday. If you have 60 or more people, the probability is greater than 99%. This is not a paradox in the sense of it leading to a logical contradiction; it is a paradox in the sense that it is a mathematical truth that contradicts common intuition. Most people estimate that the chance is much lower.
How many people in your life have you met that have the same birthday as you do? Next time, you’re in a large group, may want to ask the question.

1 comment:

David Frasch said...

Just probability is all. You are only trying to get a match with others in the list of birthdays, not a specific birthday. In other words, if I tried to get one of 23 people to have a birthday on June 17, the odds are 23 out of 365, very poor odds! But I don't care about June 17th necessarily to match with, but the other 22 days which have already been listed. So the first two birthdays have a 1:365 chance to match, the third a 2:365, the fourth a 3:365, etc... until you get to 23rd will have a 22:365.