Tuesday, December 6, 2016

Review of "The Drunkard's Walk: How Randomness Rules Our Lives" by Leonard Mlodinow


Lots of people might think they can compute the odds that something will happen. For instance, If my favorite baseball team is playing an opponent with inferior stats I might be pretty sure my guys will win....and place a small wager. But random chance - which is the rule rather than the exception - could trip me up. A so-so batter on the other team might miraculously hit a grand slam home run!

In this book Leonard Mlodinow explains how randomness affects our lives. For example, a publisher rejected George Orwell's book 'Animal Farm' with the remark "it's impossible to publish animal books in the U.S." And before he became successful author Tony Hillerman was advised "to get rid of all that Indian stuff." John Grisham's books were repeatedly rejected at first. And J.K. Rowling's first Harry Potter book was rebuffed a number of times. These writers persisted and eventually happened on the right publisher....but other (perhaps equally talented) authors didn't. Random chance at work!

Of course if we really want to figure out how likely it is that something will (or won't) happen we have to rely on math. In this book Mlodinow elucidates some of the math concepts behind probability theory and statistics - a lot of which is complex and requires re-reading a couple of times (for me anyway). So I'll just give a very basic illustration.

Suppose Don picks up two coins and tosses them. He wants to know how likely it is he'll get one head. Don figures the possible outcomes are: zero heads, one head, or two heads. So, he thinks there's a 1 in 3 likelihood. Nope.

Don has to consider all the possible sequences: heads-heads; heads-tails; tails-heads; and tails-tails. Two possible outcomes yield one head - so the chances are 1 in 2 (50%).

A basic principal of probability theory is that the chances of an event happening depends on the number of ways it can occur.

Here's another example: In 1996 the Atlanta Braves beat the New York Yankees in the first two games of the World Series (where the first team that wins four games is the victor). So, what was the chance the Yankees would make a comeback and win the series - assuming the teams are equally matched? After explaining all the possible ways the Yankees could win the remaining games, Mlodinow calculates that the Yankees had a 6 in 32 chance of winning the series, or about 19%. The Braves had a 26 in 32 chance of winning the series, or about 81%. Against the odds, the Yankees won!

Mlodinow goes on to explain that - if one team was better than the other - that would weigh into the calculations and the odds would be different. This same type of reasoning can be applied to competing businesses, television shows, movies, whatever. And even if the odds favor the 'better contender', sometimes - by pure chance - the 'worse contender' will win.

Of course 'experts' try to predict all kinds of things: whether stocks will go up; if a superhero movie will be No. 1 at the box office; whether Toyotas will sell better than Buicks; if a certain horse will win the Triple Crown; and so forth. And Mlodinow explains that - no matter how 'knowledgeable' the maven - the predictions might be wrong. The reason: our brains aren't wired to do probability problems very well.

In the book, Mlodinow discusses Pascal's triangle, the Bell Curve, random number generators, the best strategy for picking the 'correct door' on 'Let's Make a Deal', the likelihood a woman carrying fraternal twins will have two girls, whether scolding a worker who does badly and praising a worker who does well makes a difference in their future performance, one man's strategy for winning at roulette....all kinds of interesting stuff.

The book is informative and contains a lot of fascinating stories about the philsophers and mathematicians who developed probability theory, how they did it, and why (usually having something to do with gambling.... ha ha ha). I enjoyed the book and would recommend it to readers interested in the subject.

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