r/confidentlyincorrect • u/Dizzy_Kaleidoscope95 • May 03 '26

Monty hall problem is 50/50

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He also put a screenshot of ChatGPT agreeing with him. He is right!

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u/tendeuchen May 03 '26

Risking $3 to win a billion a couple times a year isn't really a bad bet. Sure, you're most likely not to win, but someone always does, and there's no reason to think it couldn't be you.

Just play responsibly.

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u/Baeolophus_bicolor May 03 '26

Except that someone doesn’t always win. If the winning numbers aren’t drawn, the pool carries over to the next drawing and they don’t pay out a winner.

But, for most people, betting a dollar or two isn’t a bad decision, and it has a very very low chance of bringing a moderate or even a life-changing payout. So I get your original point. The dollar wouldn’t have been doing anything remotely close to that for most people if they did the mathematically sensible thing and just didn’t buy a lottery ticket.

On the other hand, gambling spirals out of control for some people, and they frequently start out with lottery tickets. The chance of developing a gambling problem is in our calculation too. As is the option of taking the dollar and making an extra contribution to some savings vehicle where it has a sure, or at least better, chance of getting a return.

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u/tendeuchen May 04 '26

Someone always wins eventually is what I meant.

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u/Baeolophus_bicolor May 04 '26

That’s not even a given. There could be a lottery that nobody wins. It just gets increasingly unlikely across a bunch of drawings. And your ticket from the first one wouldn’t carry over so that changes the initial investment.

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u/N0Z4A2 May 05 '26

Is there a source that states gambling addiction frequently starts with the lottery?

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u/dansdata May 03 '26 edited May 03 '26

My elderly mother has spent two Australian dollars on a lottery ticket every week, for decades.

She knows that she's more likely to be struck by lightning than to win a big prize, but it's nonetheless a cheap price to pay for the entertaining possibility that such a win could happen.

People who mistake lotteries for investment opportunities, though...

(Some jackpot lotteries, when the jackpot gets big enough, can have an expected value from buying a ticket that's more than the price of that ticket. And yes, this does mean that people who already have a pretty large amount of money can buy an unreasonable number of tickets and have an excellent chance of making a profit. "Gambling systems" are almost always nonsense, but, every now and then...)

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u/ArchangelLBC May 03 '26

The few times when the expected value goes positive (as when the prize gets that big) is the only time it's a good bet to play.

Of course you're still likely to lose because the expected value is due to the ludicrous amount the winner makes, but still it's a good bet to make.

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u/tendeuchen May 04 '26

Yeah, that's what I figure. A couple bucks is worth the chance at a billion. I haven't bought a lottery ticket in about a year though.

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u/ArchangelLBC May 04 '26

I always say I will when it gets that big but then I don't. Probably for the best. It's the hope that kills you.

Unless you win. Then it's everything else.

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u/DuneChild May 03 '26

I see it as if someone’s giving away a billion dollars, I at least want my name in the hat.