Mathias Brandewinder on .NET, F#, VSTO and Excel development, and quantitative analysis / machine learning.
by Mathias 28. June 2009 12:41

I finished “The Drunkard’s Walk – how randomness rules our lives”, by Leonard Mlodinow, a few days after Sway; I have postponed writing about it, because a minor storm of work has hit my parts – but I really loved this book, and thought I should say a few words about it.

The book’s point is that humans are very bad at drawing conclusions from observations of random phenomena. They routinely make gross mistakes when dealing with conditional probability (92% of Americans, some of them with pretty solid mathematical credentials, get the Monty Hall problem wrong), and fall prey to the Law of Small Numbers, seeing patterns where there is none, and refusing to admit the importance of randomness in shaping our fates. In the end, the message is pretty upbeat – I loved this quote from Thomas Watson:

If you want to succeed, double your failure rate.

I really enjoyed how the book builds up following the history of probability and statistics; some of the individuals who contributed to its development are truly remarkable (just lookup Cardano for instance), and the book contains a fair share of anecdotes about them. If anything, it gave me my first introduction to Benford’s law, which I am still digesting – and which has been weirdly prominent in the news, via the Iran election issue.

In short, I strongly recommend this book if you are interested in either history of sciences, probability, or decision making.

by Mathias 18. June 2009 06:40

Mark Twain famously said “There are three kinds of lies: lies, damned lies and statistics”; in that light, I found the following anecdote – from “The Drunkard’s Walk”, a thoroughly enjoyable book so far - pretty funny.

Like most of his compatriots, Jules Henri Poincaré, the legendary French mathematician, took his bread seriously, and purchased a fresh loaf daily. Suspecting his baker was a cheat, he weights his loaves every day, and finds out the average weight is 950g instead of the 1000g advertised. He complains to the authorities – and his daily baguette suddenly becomes larger.

But now, instead of enjoying his good life, Poincaré still suspects his baker is a cheat, and keeps on measuring his bread for an entire year, and finds out that he now got mostly larger than 1000g loaves, and too few light ones. For him it’s great; but from a statistics standpoint, this doesn’t sound right: he should have roughly as many small and large loaves. Poincaré concludes that the baker is still cheating, but gives him the biggest loaf of his inventory every day to pacify him. He calls the authorities in again, who confirm he is right, and slam the baker.

The moral of the story: don’t lie to statisticians!

by Mathias 9. March 2009 13:39

No concept seems too esoteric or complex for comic strips! (from xkcd.com)

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