What is the probability that at least two persons have the same birthday?
Table of Contents
- 1 What is the probability that at least two persons have the same birthday?
- 2 What is the probability that two friends have birthday on the same date?
- 3 What is the probability that at least 2 students will have the same birthday in a class of 35 students?
- 4 What is the probability of having different birthdays?
- 5 What is the probability that none of the students share their birthday in the same month?
- 6 Is April 13 a common birthday?
- 7 How many people share a birthday with each other?
- 8 How many birthdays are there in the world?
What is the probability that at least two persons have the same birthday?
In a room of just 23 people there’s a 50-50 chance of at least two people having the same birthday. In a room of 75 there’s a 99.9\% chance of at least two people matching.
What is the probability that two friends have birthday on the same date?
What’s the chance that two people share the same birthday? The first person can be born on any day of the year, this means that the probability is 365/365 = 1. The second person has to be born on the same day as the first and there is a 1/365 chance of that happening.
What is the probability that two people have the same birth month?
The probability of the birthdays being in the same month is 1/12 (or, 1 – 11/12).
What is the probability that 3 persons have same birthday?
Then this approximation gives (F(2))365≈0.3600, and therefore the probability of three or more people all with the same birthday is approximately 0.6400.
What is the probability that at least 2 students will have the same birthday in a class of 35 students?
a 83.34\% chance
Therefore, we have to calculate the possibility that no two people will have the same birthday, exactly one person will have the same birthday and exactly two people will have the same birthday. Therefore, there is a 83.34\% chance that at least two people have the same birthday.
What is the probability of having different birthdays?
(c) Now add a fourth person, and a fifth, and so on until you have 22 people with different birthdays (p ≈ 52.4\%). When you add the 23rd person, you should have p ≈ 49.3\%….Probability of Shared Birthdays. or, How to Win Money in Bar Bets.
| Probability in a group of n people that 2 or more have the same birthday | |
|---|---|
| 50 | 0.970 |
What is the probability that the two friends have I the same birthday in different birthdays ignoring a leap year?
The probability that two different friend have different birthdays (ignoring a leap year) is : a) 364/365.
What is the probability that three people are born in the same month?
This is the case as irrespective of which month the first person is born in, the birthday of the second can be in the remaining 11 months and the third can be born in any of the remaining 10 months. There is a probability of 17/72 that the three are born in the same month.
Let’s work out the probability that no one shares the same birthday out of a room of 30 people. Let’s take this step by step: The first student can be born on any day, so we’ll give him a probability of 365/365. The next student is now limited to 364 possible days, so the second student’s probability is 364/365.
Is April 13 a common birthday?
You can see the full calendar year and how common of a birthday your special day is below….How common of a birth date is each day in the calendar year?
| Birth Date | Popularity | Average Births |
|---|---|---|
| 4/11 | 196th | 11,059 |
| 4/12 | 237th | 10,953 |
| 4/13 | 351st | 10,389 |
| 4/14 | 307th | 10,812 |
What is the probability that in a group of 3 people at least two will have same birthday?
Since all probabilities are independent, we can calculate p = (1 – 1/365)*(1 – 2/365) = 132,132/133,225 ~ 0.99159. So, the probability of at least 2 of them having the same birthday (assuming independence) is 1 – p = 1,093/133,225 ~ 0.00820, close to 1 in 122.
What is the probability that two people have the same birthday?
The first person could have any birthday (p = 365÷365 = 1), and the second person could then have any of the other 364 birthdays (p = 364÷365). Multiply those two and you have about 0.9973 as the probability that any two people have different birthdays, or 1−0.9973 = 0.0027 as the probability that they have the same birthday.
If there are 366 or more people, but only 365 possible birthdays disregarding leap year, then two or more of them mustshare a birthday. Here are some sample results:
How many birthdays are there in the world?
There are 365 possible birthdays. (To keep the numbers simpler, we’ll ignore leap years.) The key to assigning the probability is to think in terms of complements: “Two (or more) people share a birthday” is the complement of “All people in the group have different birthdays.”
What is the probability of being born on February 29th?
Leap years only happen every fourth year (more or less), so the probability that a person was born on February 29 is 1/1461 and the probability of every other day would be 4/1461.