nemo@rochester.UUCP (Wolfe) (08/28/85)
>> ... During one of my interviews for college, I was asked a typical >> stupid interview question: "What's the area of a table 3 meters wide by 4 >> meters long?" I poked around with various counter-probes like, "Do you >> mean the area of just the top surface, or the top and bottom combined?" and >> then came up with the obvious answer; 12 meters^2. > >> Anyway, it turns out the "correct" answer is 1 * 10^1 meters^2; >> since the initial data only had 1 digit of accuracy, that's all the final >> answer can have. > >Getting even more off the point, suppose we were to compute 3*4 in base 12. >The answer of course is 10(base 12) which has 1 significant figure as required. >10(base 12) translates to 12 +/- 6 (base 10) which I think is more acceptable > than the 10 +/- 5 implied by 1 * 10^1 metres^2 above. Particularly in light of the fact that (assuming the worst) the area could be 3.5 m * 4.5 m = 15.75 m^2 , or 20 m^2 (rounding to the nearest one-digit number). > >Error analysis should be *independent* of the base used to represent numbers. >For this reason I think there is something fundamentally wrong with the use >of significant figures to express accuracy. Here, here! > >Steven Bird. PHONE: +613 344-5229 (03 344-5229) Nemo -- Internet: nemo@rochester.arpa UUCP: {decvax, allegra, seismo, cmcl2}!rochester!nemo Phone: [USA] (716) 275-5766 work, 232-4690 home USMail: 104 Tremont Circle; Rochester, NY 14608 School: Department of Computer Science; University of Rochester; Rochester, NY 14627