by Steven D Levitt and Stephen Dubner. A local bestseller that attempts to find the hidden answers from (not necessarily economic) data. The answers presented are controversial to say the least, but yet not quite far fetched. That’s I guess the main selling point of the book.
The following passage is from the book. It has nothing much to do with the theme/thesis proposed by the authors. But when I read it, I began thinking whether or not it was mathematically consistent.
The ECLS project surveyed roughly one thousand schools, taking samples of twenty children from each. In 35 percent of those schools, not a single black child was included in the sample. The typical white child in the ECLs study attends a school that is only 6 percent black; the typical black child, meanwhile, attends a school that is about 60 percent black.
Another completely unrelated thing. Simpson’s paradox. A google search will reveal several good write-ups.