However, people are unlikely to confess to breaking the law, and tax inspectors do not usually check on a random sample of the population.

ECONOMIST: The informal economy is neither small nor benign

Archaeologists finds are selected sites, castles, villas, but some of the best information is from the random finds, random losses from the population in the past.

BBC: Watching the detectorists

In a meritocracy the Lords would increasingly come to represent a random sample of the population over the generations, as regression to the mean moves all to the average.

ECONOMIST: On R&D, hospital care, hemp, the House of Lords, AIPAC, Jean Baudrillard, Europe | The

If people in this population meet and breed at random, it turns out that you only need to go back an average of 20 generations before you find an individual who is a common ancestor of everyone in the population.

BBC: Family trees: Tracing the world's ancestor

The 2011 GEM report is based on a survey of 140, 000 adults in 54 economies, including 6, 000 just in the U.S. Researchers looked at responses from a random sampling of participants, as well as population data for each of the countries represented, to draw conclusions about entrepreneurial activity in those nations.

WSJ: Rise in Start-Ups Draws Doubters

Many in the general population carry some of these variants in random combinations, without any detectable effect.

FORBES: Autism And Genetics: It's Complicated

If the sample is too small or is not random, then estimates regarding the number of responsive documents contained within the population could be wildly inaccurate.

FORBES: Guest Post by Matthew Nelson

For example, instead of vaccinating everyone in a population against a disease, it may be just as effective to choose people at random and ask them to name their closest friends, then vaccinate those friends.

CNN: Obesity, STDs flow in social networks