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Originally Posted by Montrealcorp
but lets say we play heads or tail with a coin, the coin is a obviously a random varaint and i wager vs my friend wich side the coin flip, my friend might bet like 75% heads and 25% tail . me , knowing its a 50,50 bet i woulkd need to bet half tails and half heads and i wouldnt looose while him he should loose in the long run, correct?
You are confusing two concepts here.
Concept 1: betting 75% of the time that the coin will come up heads next time, and the remaining 25% of the time betting that it will come up tails next time. Betting heads on the next flip is equivalent to betting tails on the next flip, for a fair coin, so this strategy does not lose compared to making the bet on heads 50% of the time, or 100% of the time, or 0% of the time, or any other ratio. Each bet is separate.
If the coin is weighted
even a tiny bit towards heads, however, the optimum strategy, for each single flip, is to bet on heads.
Concept 2: betting that, in the next several (say 100) coin flips, heads will come up 75% of the time (so 75 times). This is much less likely than heads coming up 50% of the time. But the odds of exactly 50% are still quite small, and become smaller for increasing values of "several" coin flips. Rather, for increasing
even values; for odd values we can never have exactly half the flips be heads.
If the coin is weighted a tiny bit towards heads, then maybe it becomes more likely that 100 flips will yield 51 heads instead of 50. But it will still yield, say, between 46 and 56 heads most of the time, and 75 or more heads much less often.
The game against our nemesis is the same, except that although we are guessing nemesis' coin from our perspective, we
are a (possibly weighted) coin from nemesis' perspective. So if we try to exploit nemesis, we become exploitable as well. If nemesis decided to stick to a 50/50 strategy no matter what, then it would not matter what we do. But if nemesis is thinking, then anything we do other than 50/50 allows nemesis to change to 100/0 (or 0/100) and take advantage. If we try to re-exploit that, then... well, eventually it will balance out and we both get stuck with 50/50. There's only so much thinking you can do usefully in a game this simple.
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im not sure if i make sense for u guys
The less I read, the more sense you make. Hopefully I read enough to figure out what you're trying to say.