controlled sampling
81Natural experiment — A natural experiment is an observational study in which the assignment of treatments to subjects has been haphazard: That is, the assignment of treatments has been made by nature , but not by experimenters. Thus, a natural experiment is not a… …
82Effect size — In statistics, an effect size is a measure of the strength of the relationship between two variables in a statistical population, or a sample based estimate of that quantity. An effect size calculated from data is a descriptive statistic that… …
83Gold standard (test) — For other uses, see Gold standard (disambiguation). In medicine and statistics, gold standard test refers to a diagnostic test or benchmark that is the best available under reasonable conditions. It does not have to be necessarily the best… …
84Particle counter — A particle counter is an instrument that detects and counts particles. Applications of particle counters are separated into two primary categories:*Aerosol particle counters *Liquid particle countersAerosol particle countersAerosol Particle… …
85mining — /muy ning/, n. 1. the act, process, or industry of extracting ores, coal, etc., from mines. 2. the laying of explosive mines. [1250 1300; ME: undermining (walls in an attack); see MINE2, ING1] * * * I Excavation of materials from the Earth s… …
86chemical element — Introduction also called element, any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed. This article considers the… …
87Sample size determination — is the act of choosing the number of observations to include in a statistical sample. The sample size is an important feature of any empirical study in which the goal is to make inferences about a population from a sample. In practice, the sample …
88Randomness — Random redirects here. For other uses, see Random (disambiguation). For a random Wikipedia article, see Special:Random. For information about Wikipedia s random article feature, see Wikipedia:Random. Randomness has somewhat differing meanings as… …
89Drum machine — For the Windows drumming program, see Drum Machine (software). For the early drum machine computers that used a rotating cylinder as their main memory, see drum memory A Yamaha RY30 Drum Machine A drum machine is an electronic musical instrument… …
90Ronald Fisher — R. A. Fisher Born 17 February 1890(1890 02 17) East Finchley, London …
