rathcoole_exile
Guest Author
- Messages
- 3,925
- Likes
- 767
Aren't you reinventing the wheel. Over the very long term, it will be 50:50. You can just do a monte carlo simulation, if you must.
To be honest, one of the reasons for starting the thread was to get other people to take part themselves & compare results (and let other people share the donkey work!).
Well 500 flips isn't long term enough then (or perhaps 500 is too long term) as it had a 52:48 split when i did it. How long term do i need to go to achieve a 50:50 split?
Still 52:48 is fairly even.
What do you mean with a 50:50 split? Chances that you will achieve a perfect 50:50 split are slim, but unless you define the maximum error, you have no way to calculate how many times you need to flip a coin.
I'll give an example later on.
I would encourage you to carry on this exercise.From my 500 - i have 260 heads and 240 tails. If i continue to flip, eventually i will get back to a perfect 50:50 split. Perhaps that is when i should stop flipping.
I would encourage you to carry on this exercise.
As an example: How many people would you need to have in a room to have a high probability that two have the same birthday ?
Paul
I was having a conversation with a friend yesterday about consecutive losing trades. He knew of one chap who was previously profitable when he then managed to make 36 consecutive losing trades. The odds of that must be quite low.
....
Paul
Two. Twins.As an example: How many people would you need to have in a room to have a high probability that two have the same birthday ?
Yes this is (part of) the kind of reason why i did the flipping experiment. To see how long A can persist over B, when there is seemingly a 50:50 chance.
Also one of the best statisticians I have come across is T2W member Scripophilist. I was looking through his site one day and was interested to see that he often approaches probability from a different angle such as rather than trying to determine the probability of an event turn it round and work out the probability of the event not happening.
As an example: How many people would you need to have in a room to have a high probability that two have the same birthday ?
Paul
365+ would give a better than 50% chance i think.
And to think i started this thread with the intention of a serious discussion.
From my 500 - i have 260 heads and 240 tails. If i continue to flip, eventually i will get back to a perfect 50:50 split. Perhaps that is when i should stop flipping.
Most statistical problems are solved much faster by turning the question around. It's very common to use the standard approach, but often looking at the question from the other viewpoint will make you find the solution much easier. Example:
Suppose chances are 1 out of 10 that you get the flu after coming in touch with one infected person (we call these odds 'p'). Suppose you come in touch with two different persons who have the flu. Your chances would increase right? However, must people will multiply the odds and come up with 1/10 x 1/10 = 1/100 which is obviously incorrect.
Multiplying the odds of not getting infected (9 out of 10 or '1-p') will give you the right answer: 9/10 x 9/10 = 81/100 => meaning there is a 19% chance you will get infected after coming in contact with two persons who have the flu.
Btw, could you give me the URL of Scripophilist's site? I don't know him, but it sounds interesting...