In mathematics, the study of how to take measurements of quantity. A sub-branch of statistics, it is essential that all scientists have a basic understanding, so that they know how good their data is.

An (very simple) example of a sampling problem is: I have an instrument that is accurate to n units. My calculator is accurate to 12 decimal places. I munge the data. How accurate is my result.

Another example is, given some known correlation between homosexuality and other traits, how do I get a representative sample of the population?