| NV | nausea and vomiting; negative variation; neovascularization; next visit; nonveteran; normal value; n... |
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| PINV | postimperative negative variation |
| PSU | photosynthetic unit; primary sampling unit |
| PUBS | percutaneous umbilical blood sampling; purple urine bag syndrome |
| TCNV | terminal contingent negative variation |
| chorionic villus sampling | <procedure> A procedure for obtaining a sample of chorionic villi for the purpose of genetic testing, usually performed between 9 and 12th weeks of pregnancy. Amniocentesis testing has greatly supplanted the use of this form of genetic testing. (27 Sep 1997) |
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| haphazard sampling | The assembly of data in an unprescribed and undefined fashion that allows no sound scientific inferences other than establishing the existence of types. (Finding even one unicorn in such a set would establish that unicorns can exist, but no inference about their prevalence could be made from it.) Cf.: random sample. (05 Mar 2000) |
| sampling | The policy of inferring the behaviour of a whole batch by studying a fraction of it. Origin: MF essample, from L. Exemplum, taking out (05 Mar 2000) |
| sampling studies | Studies in which a number of subjects are selected from all subjects in a defined population. Conclusions based on sample results may be attributed only to the population sampled. (12 Dec 1998) |
| snowball sampling | A method whereby interview subjects for a statistical study are obtained from subjects already interviewed for that study.This technique is most often used with target populations made up of elusive or uncooperative subjects (e.g., IV drug users). Those subjects first contacted are asked to name acquaintances, who are then approached, interviewed, and asked for additional names. In this way, a sufficient number of subjects can be accumulated to give a study adequate power. (05 Mar 2000) |