biased sample

(redirected from Sample bias)
Also found in: Medical.

biased sample

[¦bī·əst ′sam·pəl]
(statistics)
A sample obtained by a procedure that incorporates a systematic error introduced by taking items from a wrong population or by favoring some elements of a population.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

biased sample

a population SAMPLE which is not a true reflection of the parent population (see BIAS 2), i.e. not a REPRESENTATIVE SAMPLE.

When the incidence of a certain occurrence or piece of behaviour in a population is to be investigated, e.g. voting intention, it is often impossible to examine the total population, so a sample of this population is taken. For this sample to produce acceptable data, it must be a true representation of the parent population, so it is essential that it is selected in a way that ensures this. If this is not managed, bias will result and the information collected will not truly reflect the population being studied. Thus, to select a sample by questioning people in the street will bias it against people who do not walk, do not go shopping, are at work or school all day Postal QUESTIONNAIRES attempt to overcome this type of bias, but are likely to be biased against those who do not bother to fill in questionnaires and re turn them, and against the illiterate. To keep bias to a minimum, if random sampling is not possible, it is necessary to select the sample carefully by matching all relevant parameters of the population, e.g. age, class, residence, etc, and to ensure as high a response rate as possible, probably by personal INTERVIEWS.

Collins Dictionary of Sociology, 3rd ed. © HarperCollins Publishers 2000
Mentioned in ?
References in periodicals archive ?
Third, three key components in our methodology are allowing nonlinear smooth shifts in mean, controlling for cross-sectional dependence of disturbances, and correcting the finite sample bias of estimates.
Some methods are flexible enough that they underestimate the severity of business cycles while others are so trend dominated that their estimates are subject to end sample bias. Third, assuming that output gap is autoregressive process, one period ahead forecast may be upward biased in recession and downward biased in boom.
Predictable stock returns: the role of small sample bias. Journal of Finance, 45(2), 641-661.
Thus, while at the 40 per cent, we can claim to have reached a workable response rate, the sample bias emerged as a problem.
Those images were taken with a sample bias and a tunneling current of 2.15 V and 0.11 nA, respectively.
Sample bias may have influenced the model presented (Fig.
The school selection criteria suggests sample bias. Six of the nine schools were from a state "schools of promise" list and three were not.
Among such issues are the sources of sample bias and how to compensate for the bias, appropriate units of analysis and techniques of quantitative analysis, the importance not only of large and diverse reference collections but also of information on the natural history of the fauna represented in an assemblage, and how methods link to research issues of concern to California archaeology generally.
Solution #2: To address sample bias, take these three steps:
It would be interesting for the AOP or College to research how deep this discourse is or if what I hear is heavily skewed by sample bias. Either way, the AOP have a duty to members to look into such issues, the College have a duty to the public as unhappy professionals it could be argued may be less efficient.
They report a significant sample bias that may have been the source of algorithm failure.
First, one can readily raise the question of sample bias and the limited generalizability of their conclusions; much of the work ultimately depends upon interviews with 52 men selected from an original sample of 500 white men from the Boston area born in the 1920s and early 1930s.