Same Birthday
JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
Statistics and Probaility seem to be topics that we either
like alot or dislike intensely (and suffer through in school).
For some learners, learning about a classic probaility question may
increase the chances of understanding.
For example, in tossing a fair coin 3 times, it has landed
heads every time. What is the probability that the
next toss will be tails?
But this coin toss question, where the probability of the next toss being
tails would be 50% (or would it?), can not even hold a
candle to the "Same Birthday" probability question.
Same Birthday
- What is the probability that in a group of 30 people
two people have the same birthday (for example
two people haveing a birthday of January 23)?
- It is about 70%!
- If the group size goes up to 60 people, the probability goes up
to about 99%. Check it out using the formula for 60.
Probabiltiy = 1-((365!)/365 to the power of 60/ (365-60!)).
For other numbers replace the 60 with your number.
JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
Mastering Math Magically
Roger Moore
rmoore@telusplanet.net
last modified: Jan 02, 2000
URL: http://www.telusplanet.net/public/swoitte/Same Birthday.html