this post was submitted on 19 Aug 2023
353 points (98.6% liked)

196

16721 readers
3041 users here now

Be sure to follow the rule before you head out.

Rule: You must post before you leave.

^other^ ^rules^

founded 2 years ago
MODERATORS
 
you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 31 points 1 year ago (3 children)

It might be helpful to extrapolate this out into a higher number of doors. Say there are 10 doors instead of 3, with still just the one prize. So instead of a 33% chance of getting the right answer off the bat, you have a 10% chance.

Now, after making your choice, Monty, being the good guy that he is, opens 8 of the doors that contain no prize, leaving only the door you picked, and one other closed door. Originally, your chance of getting the right door was 10%. However, that's just because you didn't know what was behind the other doors. Now, you know what was behind the other doors. Now, the number of doors that could contain the prize has shrunk from 10 to 2.

The prize is definitely behind one of the 10 doors. It could be behind the one you picked at random at the start. But that only occurs 10% of the time. 90% of the time, it's behind one of the other doors, and Monty has just shown you which of those doors it is by eliminating the other 8 possibilities. So 10% of the time, if you stick with your original choice, you're going to get a prize. But 90% of the time, you won't. So it's way better to switch when given the opportunity.

Does that make it any clearer?

[–] pory 11 points 1 year ago (1 children)

What do you mean prize? This image is about not murdering your fellow humans and nothing more. This explanation only raises further questions!

[–] [email protected] 7 points 1 year ago (1 children)

Thing referenced being the Monty hall problem. Old game show would have a prize and 2 goats behind doors. You pick one then, 1 of the goats were revealed. You get the option to swap your choice

[–] pory 2 points 1 year ago

Yes I know, I posted / made the image in OP

[–] [email protected] 11 points 1 year ago

So essentially like this:

Original door has 33% chance of being good, compared to 66% chance of the other 2 doors

One of other two doors are opened by Monty, because he's a swell guy!

The two doors still have a 66% chance of being good, but since one of them is now opened, that 66% chance now only applies to the one other door

Ergo there's a 66% chance that if you switch doors, you'll pick the right door

[–] [email protected] 1 points 1 year ago

This is a great explanation. I've always had a hard time explaining it but I feel like changing it from 3 to 10 makes it way more obvious.