How To Be Sure About Probability

Press, Volume XCIX, Issue 29270, 30 July 1960, Page 3

How To Be Sure About Probability

How To Take A Chance. By Darrell Huff. GoUancx. 173 PPThis is a light-hearted book about a serious subject The subject is the theory of probability or, to use the more evocative term, the laws of chance. It is by no means the first book to be written on the subject and on the theory of probability it is unlikely to be the last We encounter the theory of probability frequently in everyday life. Indeed, the most important personal business dealings of many individuals are based on it When a man takes out insurance on his life he accepts an arrangement that the insurance company has worked out on the theory of probability. The same thing happens when a man insures his house against fire or his car against theft or accident The odds are against him the man knows—or should know—because what he pays the insurance company covers not only the insurance actuary’s assessment of risk but commission for persons selling policies, office expenses, return on investment and such things. It might be profitable, therefore, for a man to finance himself against a hazard instead of paying an insurance company to do so. It all depends upon the theory of probability, about which Mr Huff is brightly informative. It has been remarked that if enough apes were given enough typewriters and banged upon them at random long enough they might eventually write all the books in the British Museum. But the odds would be long. Take the simple salutation: Mr Huff calculates that by chance one monkey should average one “d” every minute; three monkeys would achieve a “dear” every ten weeks; 10,000 of them would average “dear sir” per 150 years.

The whole idea was put in another way by the man who wrote: There was once a brainy baboon Who always breathed down a bassoon. For he said, “It appears That in billions of years 1 shall certainly hit on a tune.” Thus, the theory of probability says it is unjikely that our stenographers and bassoonists will be displaced by apes. Nevertheless, the story of the apes stresses one point basic to the theory of probability—that every conceivable sequence is as likely as any other. Talking of sequences naturally turns the mind to poker, and here the reader win find that Mr Huff has some helpful things to say; and if he can only remember and apply them the reader will find himself well on the way to a winning strategy at poker. It is surprising* indeed to see how often the theory of probability applies in many so-called games of chance. Besides making us light-hearted —and possibly a mite lightheaded—the theory can produce quite harsh effects. For instance, it can make us sceptical when we consider such things as opinion polls, tooth-paste, adver-

tisesnente about “never a cavity in 25 years,” and oatoutations of “average incomes.” Mr Huff says something about weather forecasting—not as much as many would like him to, but he does relieve the weather man of some of his burden and put it upon the theory of probability. Mr Huff tiptoes, albeit rather cautiously, into, the field Of extra sensory perception and as he hurries out he cautions his readers to look hard, and twice, when probabilities appear to be flouted. He quotes the story of the father, a men of observant and speculative turn, who was interested to note that when his children dropped their bread it invariably landed butter-side up. After 10 of these happy accidents in a row, against odds, be calculated, of something better than 1000 to one, the father investigated. The children, he discovered, were buttering their bread on both sides. As John Gay put it:

Lest men suspect your tale untrue. Keep probabflitp tn view. Drawings by Irving Geis, one of which is reproduced, enliven a book that will surely be as freely quoted as Darrell Huff’s earlier book, "How To Lie With Statistics.” y