random sample

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Related to random sample: stratified random sample

ran·dom sam·'ple

a selection on the basis of chance of individuals or items in a population for research; selection is made in such a way that all members presumably have the same chance of being selected.

random sample

A population sample selected by a randomisation method designed to ensure that each subject or patient in a target group has an equal chance of being selected for the treatment arm of the study.

random sample

Statistics A population sample derived by selecting individuals, such that each has the same probability of selection; a group of subjects selected in such a way that each member of the population from which the sample is derived has an equal or known chance–probability–of being chosen for the sample. See Sampling.

ran·dom sam·ple

(randŏm sampĕl)
Selection on basis of chance of individuals or items in a population for research.


unplanned, without direction or purpose.

random assignment
random mating
where each member of the population has an equal opportunity of mating with every member of the opposite sex.
random numbers
a list of numbers obtained by a standard randomization procedure; used commonly to select individual animals from a pack.
random sample
see random sample.
random sampling
a procedure for selecting units from a group in such a way that each unit has an equal chance of being selected in the sample.
random selection
selection in such a way as to produce a random sample.
random variable
a group or quantity that takes various values, each with varying probabilities.


1. a specimen of fluid, blood or tissue collected for analysis on the assumption that it represents the composition of the whole.
2. for statistical purposes a small collection of individual units taken from the population which is under investigation on the assumption that they represent the characteristics of the entire population.

EPSEM sample
acronym for 'equal opportunity of selection method'.
grab sample
sample of greasy wool taken at random by a special machine from each bale on the sale floor. Buyers price the bale on the basis of the appearance of the grab sample and the objective measurements.
multi-stage random sample
with very large populations it may be desirable to arrange the data into groups on one criterion, e.g. address by area of postcode, and to select randomly from within this group, then select from within this sample to obtain randomly a representative number of specimens, such as dogs of each age group.
random sample
the selection from a population of the units which are to constitute the sample of that population is made in such a way that each unit of the population has an equal chance of being selected. Called also simple random sample.
simple random sample
see random sample (above).
stratified random sample
the data is arranged into subsets or strata based on the possession of certain characteristics which are common to the members of the subset. The selection of units to comprise the sample of the parent population is arranged so that the proportional representation of each subset in the final sample fits a prearranged schedule.
volunteer sample
sample donated by interested parties; a biased sample because it does not represent all sections of the population. Called also self-selection.
References in periodicals archive ?
A sample for this process is "random" when the vials from different populations are mixed together forming a "pool of mixed product", and random samples of n vials are taken over time.
He based this position on his observation that "[t]here is no evidence that owls discriminate against certain species of rodents, and hence their diet constitutes a random sample of the local rodent population" (1967, p.
Information for a large-firm sample similar to those used in previous studies is also obtained, and we develop a random sample to examine derivatives use characteristics for firms not included in the large-firm sample.
But Supervisor Don Knabe, seeking a compromise, offered an amendment requiring the petitioners to pay for the random sample verification.
State law requires that every signature must be checked if a high-enough percentage of the random sample is invalid, and that could boost the bill past $270,000.
It's possible to calculate the value of pi by determining what proportion of pairs of whole numbers selected from a large, random sample has no common factors.
To certify that an average of 11 to 20 percent annual savings would occur for motorists who choose medical coverage ranging from $5 million to $250,000, the Auto Club released details of a statistical statewide random sample of policies that compared current and future rates under Proposal D.
The survey was conducted in November 2006 through a paper-based mailing to the homes of a random sample of Federal workers and uniformed service members.
State law requires that every signature must be checked if a high enough percentage of the random sample is not valid.
Breslau and her colleagues interviewed a random sample of 1,007 adults, ages 21 to 30, who belong to a Detroit-area health maintenance organization.
Twice a year MRI surveys a random sample of more than 25,000 Americans 18 years or older and reports findings based on tabulated data from over 50,000 respondents amassed during the course of one year.
The law also gives them leeway over whether to check all signatures or just a random sample.