| stratified sample | A subset of a total population, defined by some objective criterion such as age or occupation, is sampled. (05 Mar 2000) |
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| stratified | Arranged in the form of layers or strata. (05 Mar 2000) |
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| stratified ciliated columnar epithelium | An epithelium consisting of several layers of cells with the deeper cells being polyhedral in form and the surface ones columnar with motile cilia, such as that which lines the foetal oesophagus. (05 Mar 2000) |
| stratified epithelium | <pathology> An epithelium composed of multiple layers of cells, only the basal layer being in contact with the basal lamina. The basal layer is of stem cells that divide to produce the cells of the upper layers, in skin, these become heavily keratinised before dying and being shed as squames. Stratified epithelia usually have a mechanical or protective role. (18 Nov 1997) |
| stratified squamous epithelium | An epithelium consisting of several layers of keratin containing cells in which the surface cells are flattened and scale-like and the deeper cells are polyhedral in form. Keratin filaments become progressively more abundant toward the surface, which on the dry surfaces of the body may consist of a layer of dead corneocytes. (05 Mar 2000) |
| stratified thrombus | A laminated thrombus, the layers of different ages being of different colour or consistency. Synonym: stratified thrombus. (05 Mar 2000) |
| Rahn-Otis sample | An approximation of alveolar gas continuously provided by a simple device that admits just the latter part of each expiration. (05 Mar 2000) |
| random sample | A group selected randomly, solely by chance. (12 Dec 1998) |
| Haldane-Priestley sample | <physiology> An approximation of alveolar gas obtained from the end of a sudden maximal expiration into a Haldane tube. (05 Mar 2000) |
| probability sample | Each individual in the sample has a known, generally equal, chance of being selected. (05 Mar 2000) |
| sample | 1. A specimen of a whole entity small enough to involve no threat or damage to the whole; an aliquot. 2. A selected subset of a population; a sample may be random or nonrandom (haphazard); representative or nonrepresentative. Origin: M.E. Ensample, fr. L. Exemplum, example (05 Mar 2000) |
| sample, random | A group selected randomly, solely by chance. (12 Dec 1998) |
| sample size | The number of units (persons, animals, patients, specified circumstances, etc.) in a population to be studied. The sample size should be big enough to have a high likelihood of detecting a true difference between two groups. (12 Dec 1998) |
| end-tidal sample | A sample of the last gas expired in a normal expiration, ideally consisting only of alveolar gas. (05 Mar 2000) |