Random Variation / Random Error: From 1 Different Sources
The tendency for the estimated magnitude of a parameter (e.g. based upon the average of a sample of observations of a treatment or intervention effect) to deviate randomly from the true magnitude of that parameter. Random variation is independent of the effects of systematic biases. In general, the larger the sample size, the lower the random variation of the estimate of a parameter. As random variation decreases, precision increases.
See “Type I error”.... alpha (i) error
See “Type II error”.... beta (i) error
An error or omission in the medical care provided to an individual. Medical errors can occur in diagnosis, treatment, preventive monitoring or in the failure of a piece of medical equipment or another component of the medical system. Often, but not always, medical errors result in adverse events such as injury or death. See also “malpractice”; and “incidence monitoring and reporting”.... medical error
A sample that is arrived at by selecting sample units such that each possible unit has a fixed and determined probability of selection.... random / random sample
The sampling process whereby each unit in the population has an equal chance of being selected.... random sampling
In statistics, the standard error is defined as the standard deviation of an estimate. That is, multiple measurements of a given value will generally group around the mean (or average) value in a normal distribution. The shape of this distribution is known as the standard error.... standard error
An error that is not the result of an individual’s actions, but the predictable outcome of a series of actions and factors that comprise a diagnostic or treatment process.... systems error
Also known as “false positive” or “alpha (?) error”. An incorrect judgment or conclusion that occurs when an association is found between variables where, in fact, no association exists. In an experiment, for example, if the experimental procedure does not really have any effect, chance or random error may cause the researcher to conclude that the experimental procedure did have an effect. The error of rejecting a true null hypothesis.... type i error
Also known as “false negative” or “beta (?) error”. An incorrect judgement or conclusion that occurs when no association is found between variables where an association does, in fact, exist. In a medical screening, for example, a negative test result may occur by chance in a subject who possesses the attribute for which the test is conducted. The error of failing to reject a false null hypothesis.... type ii error
a common symptom of *depression, in which the patient regularly experiences different mood states at different times of day. Classically, a depressed patient will complain of particularly low mood in the morning and this gradually improves during the day.... diurnal variation of mood
n. (in research) incorrectly rejecting a null hypothesis when it is true (type I error) or failing to reject a null hypothesis when it is false (type II error). See significance.... error
any one of a group of inherited conditions in which there is a disturbance in either the structure, synthesis, function, or transport of protein molecules. There are over 1500 inborn errors of metabolism; examples are *phenylketonuria, *homocystinuria, and *hypogammaglobulinaemia.... inborn error of metabolism
(in statistical surveys) see validity.... interobserver error
(in statistical surveys) see validity.... intraobserver error
see validity.... observer error
a subgroup of a total population selected by a random process ensuring that each member of the population has an equal chance of being included in the sample. It is sometimes stratified so that separate samples are drawn from each of several layers of the population, usually on the basis of age, sex, and socio-economic group. Selection is sometimes facilitated by identifying, in advance, certain units (e.g. towns or neighbourhoods) that will together represent the whole (a so-called sampling frame).... random sample
an abnormality of the eye resulting in a blurred image on the retina as a result of abnormal focusing, which can be corrected by glasses, contact lenses, or *refractive surgery. Refractive errors include *myopia, *hypermetropia, and *astigmatism.... refractive error
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