How many people do you think it would take to survey, on an average, to find two people who share the same birthday?
Well, with the help of probability, sometimes an event is 'more likely to occur' than we believe it to. In this case, If you survey a random group of just 23 people there is actually about a 50–50 chance that two of them will have the same birthday. This is known as the birthday paradox. Don't believe it's true? You can test it and see mathematical probability in action!
The birthday paradox, also known as the birthday problem, states that in a random group of 23 people, there is about a 50 percent chance that two people have the same birthday. Is this really true? There are multiple reasons why this seems like a paradox. One is that when in a room with 22 other people, if a person compares his or her birthday with the birthdays of the other people it would make for only 22 comparisons—only 22 chances for people to share the same birthday.
But when all 23 birthdays are compared against each other, it makes for much more than 22 comparisons. How much more? Well, the first person has 22 comparisons to make, but the second person was already compared to the first person, so there are only 21 comparisons to make. The third person then has 20 comparisons, the fourth person has 19 and so on. If you add up all possible comparisons (22 + 21 + 20 + 19 + … +1 ) the sum is 253 comparisons, or combinations. Consequently, each group of 23 people involves 253 comparisons, or 253 chances for matching birthdays.
More like this
A Scientific Theory of Humor
Why Your Brain Needs More Downtime
Moving in Sync Creates Surprising Social Bonds among People
Explore the World’s
Take Your Ideas
Just press play and we take care of the words.
No Internet access? No problem. Within the mobile app, all your ideas are available, even when offline.
2 Million Stashers
Don’t look further if you love learning new things. A refreshing concept that provides quick ideas for busy thought leaders.
Best app ever! You heard it right. This app has helped me get back on my quest to get things done while equipping myself with knowledge everyday.
This app is LOADED with RELEVANT, HELPFUL, AND EDUCATIONAL material. It is creatively intellectual, yet minimal enough to not overstimulate and create a learning block. I am exceptionally impressed with this app!
Great interesting short snippets of informative articles. Highly recommended to anyone who loves information and lacks patience.
Even five minutes a day will improve your thinking. I've come across new ideas and learnt to improve existing ways to become more motivated, confident and happier.
Great for quick bits of information and interesting ideas around whatever topics you are interested in. Visually, it looks great as well.
Brilliant. It feels fresh and encouraging. So many interesting pieces of information that are just enough to absorb and apply. So happy I found this.
I have only been using it for a few days now, but I have found answers to questions I had never consciously formulated, or to problems I face everyday at work or at home. I wish I had found this earlier, highly recommended!
Read & Learn
Access to 200,000+ ideas
Access to the mobile app
Unlimited idea saving & library
Unlimited listening to ideas
Downloading & offline access
Supercharge your mind with one idea per day
Enter your email and spend 1 minute every day to learn something new.
I agree to receive email updates