Estimation

Estimation is the calculated approximation of a result which is usable even if input data may be incomplete, uncertain, or noisy.

In statistics, see estimation theory, estimator.

In mathematics, approximation or estimation typically means finding upper or lower bounds of a quantity that cannot readily be computed precisely and is also an educated guess .  While initial results may be unusably uncertain, recursive input from output, can purify results to be approximately accurate, certain, complete and noise-free.

In project management, see estimation (project management).