Probability - How does it work?!

Srsly

That's pretty random

heads... you win.

There's a one in five chance it's to do with magnets i believe

Few things are impossible, most are highly improbable though.

No but really, it confuses me.

If you roll a six-sided dice, each number has a one-in-six chance of coming up.

And if you roll a 20-sided dice, you're a geek.

There is a high probability this thread will be derailed.

Oh. And you had a 1 in 76 million chance of winning tonights euro lottery.

0 is impossible, 1 is certain, lots of gray area between.
You can multiply and add them and that's like something, eh.
Often if it doesn't seem to work, you should be looking at the probability of the opposite, which is 1 minus the thing.

Take a coin. Flip it. There are two outcomes, either heads or tails. Each is equally likely to land face up. So of the 2 outcomes, you call something, you have a 1 in 2 chance of that occurring. Flip it again, the outcome is independent of previous flips so you still have a 1 in 2 chance of getting it right. If you were to flip a coin 100 times, it'll be 50 heads 50 tails, give or take a few.

But should you wonder what is the probability of calling it right twice in a row, both flips you have a 1 in 2 chance of getting the right answer, but getting both the first AND the second correct is 1 in 4. Because both flips are 1 in 2, multiplied together gives 1 in 4. This can carry on, making the probability of 100 heads in a row, not impossible, but highly improbable.

All more complex probability stuff stems from that really. So a dice each outcome has an equal chance of 1 in 6. But say you have a dice where two of the faces were 5s and no 6s, the probability of rolling a 5 is 2 in 6, or simplified to 1 in 3, which makes it more probable to occur. etc etc etc.

Make sure you get the traditional kind.
If it got quantum isht in it it's just too dman weird.

^^but the probability of 100 heads in a row is the same as any other result.

If you just happen to find something, it's probably not obscure...

We had a whole couple of maths lessons about probability at school, we had dice and shit.

I can remember it quite well, as my mate smuggled in a tape recorder and recorded the teacher having one of his "freak outs", screaming at the class and ranting fairly incoherently for a good five minutes whilst we all silently cried with laughter behind our crossed arms.

...so if you're a hipster, probability works against you.

5 people who know each other a little, but not really well, wonder what the chances of two of them sharing a birthday might be. Anyone?

Take a coin. Flip it. There are two outcomes, either heads or tails. Each is equally likely to land face up. So of the 2 outcomes, you call something, you have a 1 in 2 chance of that occurring. Flip it again, the outcome is independent of previous flips so you still have a 1 in 2 chance of getting it right. If you were to flip a coin 100 times, it'll be 50 heads 50 tails, give or take a few.

But should you wonder what is the probability of calling it right twice in a row, both flips you have a 1 in 2 chance of getting the right answer, but getting both the first AND the second correct is 1 in 4. Because both flips are 1 in 2, multiplied together gives 1 in 4. This can carry on, making the probability of 100 heads in a row, not impossible, but highly improbable.

All more complex probability stuff stems from that really. So a dice each outcome has an equal chance of 1 in 6. But say you have a dice where two of the faces were 5s and no 6s, the probability of rolling a 5 is 2 in 6, or simplified to 1 in 3, which makes it more probable to occur. etc etc etc.

3 options not 2.

6 000 000 000 people on earth.
365 days in a year.

Two have the same birthday -- can't explain that!

If you roll a six-sided dice, each number has a one-in-six chance of coming up.

And if you roll a 20-sided dice, you're a geek.

Does the fact that the 20 sided dice roll easier than the 6 sided one have any bearing on anything?

If you could make a 24 sided dice and put each of the numbers 1-6 on 4 sides would each number have the same chance of being rolled as on a 6 sided dice? Would the distribution of the numbers over the sides have any bearing on this, ie if all four ones were on adjoining faces and all four twos were on adjopining faces and so on would the probablility of rolling any number be different to if the numbers were distributed sch that no two adjoining faces had the same number on them?

just remember, there is no such thing as random. We say it's random when we can't figure out the pattern!!

On the average 6 sided die you're actually marginally more likely to throw a 6, as the indent for each dot makes that the lightest face, and the 1 on the opposite side the heaviest.

I could never get my head around it i could only see everything as having a 1 in 2 chance
things either happen or they don't happen.

ps. the strange thing is, I forgot all of those after a mini-stroke