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Statistics
The Probability in Birthday Paradox
How many people in a group do you need to share a birthday?
Have you ever imagined that reality is not about what you think? Reality is not that complex but simple. Further, the complex problem actually has a simple solution. It’s quite strange but it’s fact — reality. Welcome to the paradox when reality seems unreal because it doesn’t work as usual.
In the birthday paradox, we would jump into the probability theory to answer the question “how many people in a group do you need to share a birthday?”. Might it be 100 or 150? Keep the answer in your mind and let’s find out the fact!
Introduction to birthday paradox
In one year, we have 365 or 366 days. If n denotes the number of people who have a unique birthday in one year (can be illustrated as the event people choose the unique number between 1–365). If there are n people in a group, the probability every person has a unique birthday is as follows.
- 1st person would have the probability of (365/365)
- 2nd person would have a probability of (364/365)
- 3rd person would have a probability of (363/365)
- …
- n-th person would have the…
