Permutations and Combinations

Abstract

Imagine that you are gathering data for a major report on the government’s economic policies. An influential friend arranges for your access to the most up-to-date files in the Bureau of the Census. Because the report is due in a few days, you are hoping that these files will give you the information you need to complete your report. Unfortunately, the files contain raw data that has not been organized or cross-referenced in any way; there is no way you can extract enough coherent information in the available time. You lose your job. Moral: having a set is not enough for most purposes; we must understand its structure.

Let me count the wheys.

Little Miss Muffet