- 13 Oct '10 12:32It's been a long time since i did my probability module in college.

If i have two independent events occuring that both have a probability of 1/10. The probability of both of them happenning is 1/100?

Is that right?

And if i have three independent events occuring, again each event at a probability of 1/10. The probability would be 1/1000?

Have i remembered correctly? - 14 Oct '10 02:47

Not sure on that one. Have you taken into account that after the first ball is picked there are less balls etc. Unless the lottery replaces the ball taken. (Haven't played this sort of lottery.) Don't ask me to calculate it though.*Originally posted by PinkFloyd***So, that means my chances of winning the "Pick 3"Lottery is 1 in 1000? {choose 3 numbers from 0-9 and match them all}** - 14 Oct '10 07:17

If the numbers can only be picked once (though it does not appear to be the case here), it's still quite easy to calculate; the chance would be 1/(10*9*8).*Originally posted by Taoman***Not sure on that one. Have you taken into account that after the first ball is picked there are less balls etc. Unless the lottery replaces the ball taken. (Haven't played this sort of lottery.) Don't ask me to calculate it though.** - 14 Oct '10 13:19

If the order mattered. If it didn't, multiply by 6 (the number of permutations of three different numbers).*Originally posted by KazetNagorra***If the numbers can only be picked once (though it does not appear to be the case here), it's still quite easy to calculate; the chance would be 1/(10*9*8).** - 14 Oct '10 16:06

Yet we shouldn't misinterpret that claim. We almost certainly do have over 200 lotery winners of loteries with worse than 1 in 100 million odds.*Originally posted by mtthw***1/(100 million)^200...or 1/10^1600**

Also know as "damn near to impossible".

What is 'damn near impossible' is for the same person to win all those lotteries (and hasn't happened). - 14 Oct '10 16:52 / 1 edit

Or, equivalently, to predict in advance who the 200 winners will be.*Originally posted by twhitehead***Yet we shouldn't misinterpret that claim. We almost certainly do have over 200 lotery winners of loteries with worse than 1 in 100 million odds.**

What is 'damn near impossible' is for the same person to win all those lotteries (and hasn't happened).

It's true, though, you've got to keep an eye on your sample space. Massively unlikely events happen all the time. As in the Richard Feynman quote in a lecture: "I was walking to class today and the funniest thing happened: I saw a car with the license plate ‘ARW 357’. Can you imagine? Of all the possible license plates, what are the chances of seeing that one?" - 14 Oct '10 18:13

The point of that quote is that it doesn't make sense to calculate the probability of an event after it already happened.*Originally posted by mtthw***As in the Richard Feynman quote in a lecture: "I was walking to class today and the funniest thing happened: I saw a car with the license plate ‘ARW 357’. Can you imagine? Of all the possible license plates, what are the chances of seeing that one?"**

He says so himself when retelling that story. - 15 Oct '10 10:40

I know.*Originally posted by adam warlock***The point of that quote is that it doesn't make sense to calculate the probability of an event after it already happened.**

He says so himself when retelling that story.

The other part of the point is that you have to consider probabilities in relation to the sample space your interested in. Because if there are millions of possible things that can happen then million-to-one incidents are not unlikely.

There's a very good essay on this by Ian Stewart and Jack Cohen. Unfortunately I can't find a reference to it. But I remember one part where one of them had a bet that "a coincidence will occur" while walking through an airport in Sweden. They then bumped into someone they knew and hadn't see for ages.