Why murder is more tempting in New York, look who gets handouts, the line on lines, and other matters. ASK MR. STATISTICS
By DANIEL SELIGMAN REPORTER ASSOCIATE Patty de Llosa

(FORTUNE Magazine) – Dear Probabilissimo: I believe that an unrecognized problem for our economy is the fact that consumers like me experience great difficulty when they try to buy something. For example, when the little woman sends me to the supermarket, I keep getting on queues where somebody up front is into an endless argument about whether it's okay to use an AT&T credit card to buy nothing but $2.71 worth of rutabagas. When visiting the neighborhood racetrack, I always seem to end up in lines where the bettor at the window is taking his own sweet time loading up on doubles and trifectas and furthermore demanding a recount to ensure that he's got the right tickets. On a recent afternoon in January, this caused me to get shut out in the Seventh at Aqueduct, a race in which I happened to have solid information about which jockeys were suffering from hypothermia, although to be utterly fair about this, one of them did manage to stagger into the winner's circle. I have three questions: (1) Why am I so often in the wrong line? (2) Would it make sense for supermarkets and racetracks to move to the system now used in banks and airline terminals, wherein everybody stands in a single line, and when you get to its head, you move to whichever server is free? (3) What exactly are rutabagas? -- WORN-OUT SHOPPER Dear Shopworn: You personally sound like a hard-luck character, but many folks believe they all too often get in the wrong line, and the science of statistics helps us understand why they feel this way. A new and fascinating Macmillan textbook called Introduction to Probability, by Douglas G. Kelly of the University of North Carolina at Chapel Hill, being plugged here because Doug has cited several statistical items in Keeping Up, notes that in any given environment, waiting time in lines is highly variable. If you charted the relative frequencies of the different waiting periods, you would typically be looking at a curve showing many waits of brief duration but with the frequencies declining geometrically to produce a few very long waits. One problem in the book concerns two friends who finish their supermarket shopping at the same time, then get in two different lines with only a single shopper ahead of them. The solution notes a 67% probability that one of the friends will have to wait at least twice as long as the other. Kelly also helps one understand why the single-line system now used in banks is superior to multiple lines. Imagine 22 people in a bank with six windows open. Let's say it takes 45 seconds to complete an average transaction at the teller's window. If the 22 are arrayed in separate lines, each with at least three customers, then an average individual joining a line has an expected waiting time of two minutes 15 seconds. If instead the standard situation is 16 in a single line and six at the windows, then the customer first getting in line can expect an average wait of two minutes flat; furthermore, this system involves less variability in waiting times. But extending the system to supermarkets and racetracks is not in the cards. Supermarkets would require different layouts, with much more uncluttered floor space than is now available. Racetracks with single lines would find that customers at the windows, with nobody right behind them to scream imprecations, would dawdle even more than they do now in an effort to bet at the last minute (and thereby have the most complete information about betting odds). Rutabagas, also known as Swedish turnips, are roots frequently eaten by livestock and impoverished horseplayers.