Saturday, August 13, 2011

Anyone for bridge?

I recently posted the odds of having ten straight years of exceptionally hot weather by comparing it to drawing two straight poker hands with four aces (about 3 in a billion).

Since not everyone is a poker player, I decided to calculate the odds of drawing this hand in bridge.  In bridge each player gets 13 cards.  Let's say that the hottest year is like drawing the ace of spades, the second hottest is the ace of hearts, and so on down to the 13th hottest, which would be the jack of spades.  Now there are only 52 playing cards in a deck, while there are 130 years of data, so the odds of a recent year randomly being the hottest ever are actually much less than drawing the ace of spades. But even so, if you randomly drew a card for each of the last 13 years, you would have all the aces--the 4 hottest years, all the kings--next 4 hottest years, all the queens--next four hottest years, and the lowly jack of diamonds for poor 2000, which was "only" the 15th hottest year on record.  You could bid 7 no trump and lay down your cards with no contest!

What are the odds of that?   From the math is fun web site, I learn that there are 635,013,559,600 possible hands (that's 635 billion+!) of bridge (combinations of 13 cards from a deck of 52).  So in our last 13 years there are only two other hands possibly higher--i.e. where 2000 would be the jack of spades or the jack of hearts.  So counting our jack of diamonds, we see that the odds are 3 out of 635 billion of drawing this hand.

Math is fun!


Rank             Year                Degrees F above 20th Century average
1                   2005                1.12
                     2010                1.12
3                   1998                1.08
4                   2003                1.04
                     2002                1.04
6                   2006                1.01
                     2009                1.01
8                   2007                 .99
9                   2004                 .97
10                 2001                 .94
11                 2008                 .86
                     1997                 .86
13                 1999                 .76
14                 1995                 .74
15                 2000                 .70

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