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intraobserver variation

intraobserver variation  

Syn: intraobserver error. Differing readings of the same phenomenon by the same observer on second or other subsequent review. With chest x-rays, the same observer reports different findings on ...
Proportion

Proportion   Quick reference

A Dictionary of Epidemiology (6 ed.)

Reference type:
Subject Reference
Current Version:
2016

...0.2), as a “common fraction” (1/5), or as a Percentage (20%). By definition, a proportion (p) must be in the range (decimal) 0.0 ≤ p ≤ 1.0. Since numerator and denominator have the same dimension, any dimensional contents cancel out, and a proportion is a dimensionless quantity. Where numerator and denominator are based on counts rather than measurements, the originals are also dimensionless, although proportions can be used for measured quantities (e.g., the skin area of the lower limb is x percent of the total skin area) as well as for counts (e.g.,...

Sample

Sample   Quick reference

A Dictionary of Epidemiology (6 ed.)

Reference type:
Subject Reference
Current Version:
2016

...or socioeconomic status, and selecting a random sample out of each subgroup. If the proportion of the sample drawn from each of the subgroups, or strata, is the same as the proportion of the total population contained in each stratum (e.g., age group 40–59 constitutes 20% of the population, and 20% of the sample comes from this age stratum), then all strata will be fairly represented with regard to numbers of persons in the sample. 7 . Systematic sample The procedure of selecting according to some simple, systematic rule, such as all persons whose names begin...

intraobserver variation

intraobserver variation   Quick reference

A Dictionary of Public Health (2 ed.)

Reference type:
Subject Reference
Current Version:
2018

...intraobserver variation ( intraobserver error ) Differing readings of the same phenomenon by the same observer on second or other subsequent review. With chest X-rays, the same observer reports different findings on re-examination of the same set of X-rays about once in 20 films; i.e., the intraobserver variation rate is about 5%. ...

mammography

mammography   Quick reference

A Dictionary of Public Health (2 ed.)

Reference type:
Subject Reference
Current Version:
2018

...evidence of cancer. The commonly used method involves X-ray mammography, low-penetration soft tissue radiological examination, which exposes a woman to only a minimal dose of ionizing radiation. An alternative, thermography , which relies on measurements of radiant heat emanating from the breast, is less reliable and is seldom used. Mammography is recommended for women in the second half of their reproductive life, roughly age 30 to 50 years, at two-year intervals and less frequently for the following 20 years. Evaluations have shown the value of mammography...

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