Astonishing Facts....
Discussion
t. 
Greg_D said:
This whole hypothetical bear business got me curious, so I looked a few things up and a .45 wouldn’t get the job done by common consensus. so a sawn off shotgun running slugs is the only effective option that can be ‘shrunk’ for weight and packaging purposes
What about when Daddy bear starts with "Who's been sleeping in my porridge?" Rawwr said:
In a room of 23 people, there’s a 50/50 chance of two people having the same birthday.
In a room of 75 people, there’s a 99.9% chance of two people having the same birthday.
Indeed, in an old club of mine of less than 30 members, 3 of us shared the same birthday (4 if you count Princess Anne)In a room of 75 people, there’s a 99.9% chance of two people having the same birthday.
Nanook said:
bertie said:
Rawwr said:
In a room of 23 people, there’s a 50/50 chance of two people having the same birthday.
In a room of 75 people, there’s a 99.9% chance of two people having the same birthday.
You’ll have to explain how? In a room of 75 people, there’s a 99.9% chance of two people having the same birthday.
23 people, means 253 possible couples.
1-(1/365) = 364/365 = 0.997
The chance of 2 people having different birthdays is 0.997:1
(364/365)^253 = 0.4995
The chance of 2 people having different birthdays, from our group of 23 people, or 253 potential couples, is 0.4995.
You don't multiply, it's exponential. It's tricky to get your head around.
I can follow the maths but not the numbers used or why you’ve used each particular formula. Can you actually explain as I really would like to get my head round your reasoning
Antony Moxey said:
ot sure you’ve explained anything, all you’ve done is shown a load of calculations. F’rinstance 1-(1/365) = 364/365 = 0.997.
I can follow the maths but not the numbers used or why you’ve used each particular formula. Can you actually explain as I really would like to get my head round your reasoning
https://betterexplained.com/articles/understanding...I can follow the maths but not the numbers used or why you’ve used each particular formula. Can you actually explain as I really would like to get my head round your reasoning
Nanook said:
I'll try.
The first part, we're starting with the number 23, as the number of people in the room.
If you want to know how many possible couples there are, you can add 22+21+20+19+...+3+2+1 = 253, or you can multiply the number of people in the room, by the number of people in the room, not including you, and halving it.
The second part, what are the odds of someone sharing the same birthday as you? Ignoring leap years, it's going to be 1/365. Which is 0.0027. 0.27%. Meaning the chances of someone not sharing your birthday, is 99.73%, a factor of 0.997, because if there's a 1/365 chance they share it, there's a 364/365 chance they don't. 364/365 = 0.997
Now, if you want to find out what the chance of a certain number of people not sharing a birthday is, you have to use both of these numbers.
You take the chance of not sharing a birthday with someone, which is 364/365.
Actually, before we get to the answer for this number of people (23), consider just 3 people.
With 3 people, the possible number of couples is 3.
Either by adding 3 to 2, then halving it, or adding 2 to 1.
Now, we take that chance of 2 people sharing a birthday, and cube it.
(364/365)^3 = 0.991. There's still a 99.1% chance that none of you share a birthday.
For 5 people, there are 10 couples, using the formula, or draw it out. Draw 5 circles, space them out evenly in a circular pattern. Now draw straight lines connecting every circle to every other. Congratulations, you just drew a pentagram. Also, note there are ten lines.
(364/365)^5 = 0.973. The chance of none of you sharing a birthday is dropping, it's now at 97.3%
Consider again, our 23 people, if you were to draw out 23 circles, evenly spaced, and connect every circle to every other, with a straight line, you'd have drawn 253 lines. 253 couples.
Bback to our 364/365, that's valid for you and one other person. There's only a 1 in 365 chance you share a birthday.
But if you want to know the odds of someone sharing a birthday with someone else, you have to calculate that number to the nth power, where n is the number of possible relationships.
You know what, I'm not focused, I'm just gonna stop there. I'm not gonna delete it, I might pop back when I'm less tired and facepalm at how bad a job I've done of explaining. I could never be a teacher. If you don't get it first time, I'm just gonna end up saying it louder and slower. Sorry.
Brilliant!The first part, we're starting with the number 23, as the number of people in the room.
If you want to know how many possible couples there are, you can add 22+21+20+19+...+3+2+1 = 253, or you can multiply the number of people in the room, by the number of people in the room, not including you, and halving it.
The second part, what are the odds of someone sharing the same birthday as you? Ignoring leap years, it's going to be 1/365. Which is 0.0027. 0.27%. Meaning the chances of someone not sharing your birthday, is 99.73%, a factor of 0.997, because if there's a 1/365 chance they share it, there's a 364/365 chance they don't. 364/365 = 0.997
Now, if you want to find out what the chance of a certain number of people not sharing a birthday is, you have to use both of these numbers.
You take the chance of not sharing a birthday with someone, which is 364/365.
Actually, before we get to the answer for this number of people (23), consider just 3 people.
With 3 people, the possible number of couples is 3.
Either by adding 3 to 2, then halving it, or adding 2 to 1.
Now, we take that chance of 2 people sharing a birthday, and cube it.
(364/365)^3 = 0.991. There's still a 99.1% chance that none of you share a birthday.
For 5 people, there are 10 couples, using the formula, or draw it out. Draw 5 circles, space them out evenly in a circular pattern. Now draw straight lines connecting every circle to every other. Congratulations, you just drew a pentagram. Also, note there are ten lines.
(364/365)^5 = 0.973. The chance of none of you sharing a birthday is dropping, it's now at 97.3%
Consider again, our 23 people, if you were to draw out 23 circles, evenly spaced, and connect every circle to every other, with a straight line, you'd have drawn 253 lines. 253 couples.
Bback to our 364/365, that's valid for you and one other person. There's only a 1 in 365 chance you share a birthday.
But if you want to know the odds of someone sharing a birthday with someone else, you have to calculate that number to the nth power, where n is the number of possible relationships.
You know what, I'm not focused, I'm just gonna stop there. I'm not gonna delete it, I might pop back when I'm less tired and facepalm at how bad a job I've done of explaining. I could never be a teacher. If you don't get it first time, I'm just gonna end up saying it louder and slower. Sorry.
Just brilliant!
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