The Story Of Two Graphs Drawn By A Tamil Man
Prof. Mahesan Niranjan
At the famous Bridgetown pub yesterday afternoon, a Tamil man showed me two graphs he had drawn on beer mats. He is none other than Sivapuranam Thevaram, the Sri Lankan Tamil fellow who is my regular drinking partner. Statisticians among you might recognize the graphs as representing some kind of probability densities. Let me tell you the story behind these graphs.
Thevaram’s first graph was a simple one, widely known by the familiar phrase the “Bell Curve.” It represents how some stuff — like the price of onions in the Jaffna market — is distributed. Around where the graph peaks, you will find the price most of the time. Occasionally, say as a result of heavy rains leading to a bad crop, the price will be at the higher end of the graph. And at times, for instance, when Lalith Athulathmudali — the former trade minister in President Pinocchio’s evil government — decided to import onions in large quantities from India to “teach the Jaffna man a lesson,” you might have found the price at the lower end of the scale.
Now, the bell curve has famously been used to show how intelligence is distributed among a population. Some have used this to argue that there is such a natural distribution of the stuff and that if you were born at the lower end of it, there is nothing much you can do to redeem yourself. “It is all in the genes,” goes that particular theory, from which its proponents jump to the conclusion that certain ethnic groups are so well represented at the lower end of the spectrum that there is no point in investing any resources in their communities. These theorists are oblivious to the fact that the instruments to measure this inherited substance are designed in such a way as to put the instrument-maker at the advantageous end of the scale.