Sampling Error

Definition: Sampling error is an error that occurs when using samples to make inferences about the populations from which they are drawn. There are two kinds of sampling error: random error and bias.

Random error is a pattern of errors that tend to cancel one another out so that the overall result still accurately reflects the true value. Every sample design will generate a certain amount of random error.

Bias, on the other hand, is more serious because the pattern of errors is loaded in one direction or another and therefore do not balance each other out, producing a true distortion.