The Monty Hall Christmas Problem – Solved!

From Anne Giles Clelland:

In yesterday's post, I explained that I wasn't sure what present to choose, so I gave Mr. Handshake 2.0 the Monty Hall Problem for Christmas.

I said, "Behind one door is something you already have.  Behind another door is something you may want that's moderately priced.  Behind another door is something you may want that's high-priced.  Which door do you choose?"

Mr. Handshake 2.0 liked the tempting size of Door #3, but no small-brained partridge in a pear tree, he chose Door #1, as did the question-asker of the high-IQ-ed Marilyn vos Savant.

I had run my scheme by another genius because in the Monty Hall Problem, the choices are 1 good and 2 bad.  I had populated my doors with 1 great, 1 good, and 1 funny.  It still worked!  But I was hoping Mr. Handshake 2.0 would pick Door #2 or Door #3 because I knew that behind Door #1 was the funny choice!

As had been necessary with the other genius, I had to reveal my "good" choice.  I said, "I'm going to open the door of the thing you want that's moderately priced.  That means that behind one of the remaining closed doors is something you already have, and behind the other is something high-priced."

The Monty Hall Christmas Problem - one door open

I opened Door #2 and in my best game show announcer voice said, "A new Droid X!" 

(I love my Droid X and knew Mr. Handshake 2.0 appreciated its features, so I thought he might like one, too.)

I said to Mr. Handshake 2.0, "Do you want the Droid X?  Do you want try for the high-priced present?  Do you want to stick with your first choice of Door #1?  Or do you want to switch to Door #3?"

Being the partridge in a pear tree that I am, and loyal to a fault, I would have stuck with Door #1.

Mr. Handshake 2.0 said, "Switch, of course.  Door #3."

The other genius had given the exact same answer!

Given the Monty Hall Problem, a genius knows to switch doors

"A brand new iPad!" I said.

"WOW!" said Mr. Handshake 2.0.

I actually gave him the choice of the presents behind Door #2 and Door #3, but he stuck this time.  I had a feeling he wanted the iPad more than the Droid X, but I also knew he would want the new release of the iPad 2, rumored to happen early next year, not the current version, so I didn't want to buy one now and have him be disappointed.  So he'll get delivery of his Monty Hall Christmas Problem iPad in a few months.

"What's behind Door #1?" Mr. Handshake 2.0 asked.  "What do I already have?"

Ah. Of all the gifts Mr. Handshake 2.0 brought to our marriage, besides his wonderful self, this one I treasure most.

And when I opened Door #1, Mr. Handshake 2.0 laughed.

The best Monty Hall Problem choice - Mr. Handshake 2.0's Cat

If you can't quite make her out, that's Mr. Handshake 2.0's Cat.  I carefully tuck her every day into a down blanket after she slides off from sleeping on me.  She's my client. :)

Parametric Holiday Greetings from Coldwell Banker Townside, Realtors
The Monty Hall Christmas Problem

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