Brain Teaser

[TheCainer]

How many of you remember Marilyn vos Savant? She supposedly had one of the highest IQs ever measured and used to write a column for I believe Parade magazine (maybe she still does?). Typically she would pose a math related problem for her readers to ponder. Anyway, I came across the linked problem on probability and thought I would share it for those who don't have much to do today.

Enjoy!

Game Show Problem

 

[beardownboiler]

Originally posted by TheCainer:
How many of you remember Marilyn vos Savant? She supposedly had one of the highest IQs ever measured and used to write a column for I believe Parade magazine (maybe she still does?). Typically she would pose a math related problem for her readers to ponder. Anyway, I came across the linked problem on probability and thought I would share it for those who don't have much to do today.

Enjoy!

2/3

I was an English Lit major who took only two math or math-related classes at Purdue (one was a stats class), and I got it right. What's with all these people who are actually supposed to know this getting it wrong? Part of the key it to suspend your expectations of the answer, and not to reassign the probabilities after one door is opened. It's still out of 3, because the host will always choose a losing door first. Sorry, I'm terrible at explaining this stuff.

EDIT: I guess there was further explanation down in the column. So, look to that . . she explains it much more eloquently than I can.



This post was edited on 7/30 2:04 PM by beardownboiler

 

[qazplm]

the old "Monty Hall Problem"

It is definitely counter-intuitive!

 

[BoilerTom90]

Thanks, that was a fun problem

and caused much angst around the dinner table tonight.

 

[db]

The only hard part of the original problem is that you had to infer that the host would never open a door with the winning prize.

Once she clarifies that assumption, it is all downhill.

Funny thing is, at any point during the "furor," if any reader had ended up on a gameshow and been placed in this situation, they would have to switch...because that either leaves you better off or no worse off, depending on which answer that reader believed at the time.

 

[beardownboiler]

Originally posted by db:
The only hard part of the original problem is that you had to infer that the host would never open a door with the winning prize.

Once she clarifies that assumption, it is all downhill.

Funny thing is, at any point during the "furor," if any reader had ended up on a gameshow and been placed in this situation, they would have to switch...because that either leaves you better off or no worse off, depending on which answer that reader believed at the time.

Yeah. I mean, you have a 2/3 chance of being wrong with your first choice. So, once you know which one not to pick out of that 2/3 . . . just pick the other. I thought the furor was hilarious, because I think that it requires some real closed mindedness in order to not accept the correct answer.. . . and these were learned people. (getting it wrong and not accepting the right answer are two different things, btw)