535
Whats your such opinion (discuss.tchncs.de)
submitted 10 months ago by cryptix@discuss.tchncs.de to c/asklemmy@lemmy.ml
you are viewing a single comment's thread
view the rest of the comments
[-] my_hat_stinks@programming.dev 25 points 10 months ago* (last edited 10 months ago)

You're not really arguing against the whole crowd there, a lot of people (wrongly) hold the same opinion. The problem is thinking of the door swap as an independent event when it's not; the result is directly related to the original choice of door. If we label the doors A, B, and C and put the prize behind door A, here's the possible options:

Initial Choice A
- Stick: win
- Swap: lose

Initial Choice B:
- Stick: lose
- Swap: win

Initial Choice C:
- Stick: lose
- Swap: win

Two out of three times swapping wins.

Edit: I see you added a table to your comment, but you're miscounting pretty badly there. You're giving double weight to initial choice being correct.

It is technically true that when you pick A the presenter can open either B or C, but then you need to account for that in your odds; it's 50% either way so the win/loss rate is halved. In other words:

Initial Choice A - 33%
- Presenter opens B - 50%
   - Stick: win (16.5%)
   - Swap: lose (16.5%)
- Presenter opens C - 50%
   - Stick: win (16.5%)
   - Swap: lose (16.5%)

Initial Choice B - 33%
- Presenter opens C - 100%
   - Stick: lose (33%)
   - Swap: win (33%)

Initial Choice C - 33%
- Presenter opens B - 100%
   - Stick: lose (33%)
   - Swap: win (33%)

As shown, including which door the presenter opens does not affect the odds. When sticking, you win (16.5% + 16.5% = 33%) and lose (33% + 33% = 66%), when swapping you win (33% + 33% = 66%) and lose (16.5% + 16.5% = 33%).

this post was submitted on 07 Dec 2023
535 points (87.6% liked)

Asklemmy

43627 readers
1831 users here now

A loosely moderated place to ask open-ended questions

Search asklemmy ๐Ÿ”

If your post meets the following criteria, it's welcome here!

  1. Open-ended question
  2. Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
  3. Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
  4. Not ad nauseam inducing: please make sure it is a question that would be new to most members
  5. An actual topic of discussion

Looking for support?

Looking for a community?

~Icon~ ~by~ ~@Double_A@discuss.tchncs.de~

founded 5 years ago
MODERATORS