This kind of thinking is wasteful. Every d20 has a finite lifespan. It was created, and it will, at some time in the future be destroyed, as all things are. That means it has a finite number of rolls in its lifetime, with an equal distribution of all possible outcomes. When you “practice roll” and get a nat 20, you have wasted one of the limited number of nat 20s that die has in it. Think of the 20s. Don’t practice roll.

D4 is the devil’s dice.

The math checks out, but the problem is the danger of rolling a nat 20 on your practice roll. The odds of getting two nat 20s in a row are almost as low as the odds of getting two nat 1s, so you may be screwing yourself out of a crit

I think the problem is that people forget Monty Hall has information that the contestant does not. The naive assumption is that he’s just picking a door and you’re just picking a door. The unsophisticated viewer never really stops to think about why Monty Hall never points to a door and reveals a prize by mistake.

One way I’ve had success explaining it is to expand the problem to more than three doors. Assume 100 doors. Monty Hall then says “Open 98 doors” and fails to reveal a prize behind any of them. Now its a bit more clear that he knows something you don’t.

Jesse, that’s not how probability fucking works.

The trick is to say “this is just a practice roll” where the die can hear you, but wink at the GM so they know it’s the real roll. That way, the die will be a spiteful little punk and throw out the nat20 for the “practice”.

But don’t do that too often, or the die will figure out the trick.

Weirdly enough, it’s just the way probability works.

Once something stops being a possibility, and becomes a fact (ie. dice are rolled, numbers known) - future probability is no longer affected (assuming independent events like die rolls).

e.g. you have a 1/400 chance of rolling two 1s on a D20 back-to-back. But if your first roll is a 1, you’re back down to the standard 1/20 chance of doing it again - because one of the conditions has already been met.

That’s very interesting to me (I am a bit mathematically illiterate when it comes to probability). Wouldn’t it still have a lower chance of being a 1 if you said you want your second roll to be the one that counts beforehand? Or would different permutations screw with the odds, say rolling a 12 then a 1, rolling a 15 and a 1, etc, counting towards unfavourable possibilities and bringing it back to 1/20?

The thing you’re getting by switching is the benefit of the information provided by the person who revealed an empty door.

Before a door is open, you have a 1/3 chance of selecting correctly.

After you select a door, the host picks from the other two doors. This provides extra information you didn’t have during your initial selection. The host points to a door they know is a dud and asks for it to open. So now you’re left with the question “Did I pick the correct door on the first go? Or did the host skip the door that had the prize?” There’s a 1/3 chance you picked the right door initially and a 2/3 chance the host had to avoid the prize-door.

Me every time I think about this.

That’s stupid. But obviously how the dice strikes the table impacts its balance and therefore the probability of rolling specific numbers. So we must figure out what side need to strike the table first to decrease the probability of getting an undesirable roll. Boom, I out physicsed you’re probabilities.

Right but the way I took the meme was that you would roll until you get a 1, then deciding the next roll is the “real” one.

Yeah I think the easiest way of understanding how monty affects the choice is to imagine 100 doors, and after you pick one monty opens 97 other ones. Wouldn’t you want to change after that?