I think it's sad they don't require a class in formal logic in order to graduate high school. And that many don't even offer these courses as an option. What he is saying in the first part of the video is true. Using simple step by step logic will clearly show that.

This Monty Hall Problem was first broadcast in a popular magazine by a reader with the handle of Savant. Thousands of readers wrote in, most of them saying it didn't matter if the contested kept his door or switched. Hundreds of these writers said they had PhDs. This majority opinion was wrong, as applying formal logic would have illustrated. A PhD in science or the arts only makes you competent in that field in which you studied. It doesn't make you wise in general. So use logic instead of doing something because you are advised as they are telling you "according to science". 

 

 

You pick a door and then the host (Monty Hall) shows you what's behind one of the other doors. (It will be a goat or it will be small  money because Hall knows what's behind  each door, and he would never reveal a door in front of the big money). No matter which door you choose, and no matter if that chosen door has the big money or not, there is either one or two other doors that has something instead of big money. Hall is going to only reveal a non winning door.

And after he does, you should definitely switch! 
=======================================

Let's say you picked door #1<=================
There are now eactly 6 possibilities. If you switch your pick after Hall's reveal, then you have 4 out of  6 chances to win big money. If you keep your door, then you have only 2 out of 6 chances.

EDIT the last line should have been:

door 1...door 2...door3

small $...goat....big $

Edited February 27, 20233 yr by Fielder