How do you take random samples? - Answers

A random sample is a sample drawn in such a way that every item in the population has an equal and independent chance of being included in the sample.In real life, the ability to choose a random sample is dependent on the type of object being sampled: If the population is small and in a single place, say balls in an urn, you just pick a ball out of the urn. But say you want to choose a random sample of the people in a small town. This is far more problematic - you have to have a list of all the people, and then choose random items from the list. But you may not have access to that list. Please see the story of the Literary Digest Presidential Election Poll at the related link to appreciate the problem of a non-random sample.