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A '''statistic''' is a calculation made on the basis of a set numbers derived as a sample from some distribution, and usually used in order to estimate something about the distribution from which the sample is taken.   

A '''statistic''' is a calculation made on the basis of a set numbers derived as a sample from some [[distribution]], and usually used in order to estimate something about the distribution from which the sample is taken.   

For example, suppose a random sample of three children is chosen from a particular class, and their heights measured as 1.42cm., 1.54cm., and 1.48cm; then the [[arithmetic mean]] of these heights is 1.48cm. We might then go on to use  this value of 1.48cm to represent the [[average]] height of a child in that class.

For example, suppose a [[random sample]] of three children is chosen from a particular class, and their heights measured as 1.42cm., 1.54cm., and 1.48cm; then the [[arithmetic mean]] of these heights is 1.48cm. We might then go on to use  this value of 1.48cm to represent the [[average]] height of a child in that class.

Clearly the validity and reliability of such estimations will depend enormously on a range of factors such as the type of distributions, the number in the sample, and on sampling methods used.

Clearly the [[validity]] and [[reliability]] of such [[estimation]]s will depend enormously on a range of factors such as the type of distributions, the number in the sample, and on sampling methods used.