Does the law of 2/3rds have an influence on the odds?

[hanshuckebein]

hi guys,

I recently found this website.

link:://winningatroulette2.blogspot.com/

in the part  "Mathematics of the roulette wheel" the guy claims, that the law of 2/3rds actually changes the odds.

at first I thought that his explanation sounds logical, but then again .... no ... this might be just another fallacy someone had fallen for.

maybe some of you guys with much better math-knowledge than mine would like to share their opinion on it?

cheers

hans

[Colbster]

The 2/3 trick has no mathematical basis.  You do have a 50/50 chance of picking the winning card from 2 cards except the 1/3 of the time where the winning card is the one chose at the beginning.  You have the winning card among your 2 remaining cards 2/3 of the time, meaning you will pick the winning card 50% of 2/3, which is 1/3, the exact same number of times that you would have done it out of the original 3.

If your cards are A, 2, and 3, your possible drawing combinations are:

A23
A32
2A3
23A
3A2
32A

Your only winners on the 2nd draw (1st after removing a card) are 2A3 and 3A2, meaning 2 out of the possible 6.

Sounds cool, but you don't gain an advantage.

Sorry!

[hanshuckebein]

well, I was afraid of that. but now I understand why it doesn't work. thanks for taking the time to explain it. 

cheers

hans