cluster sample


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cluster sample

a method of SAMPLING which selects from groups (clusters) existing in the parent population, rather than assembling a RANDOM SAMPLE. This tends to be quicker and cheaper, but may lead to a BIASED SAMPLE if the clusters are not representative of the parent population. For example, polls taken of attitudes to government policy may be carried out in selected areas of the country thought to be representative, but, because of local political dynamics, this may not be the case.
Collins Dictionary of Sociology, 3rd ed. © HarperCollins Publishers 2000
References in periodicals archive ?
We conducted a cross-sectional, analytical study among a random cluster sample of 190 PCPs working in Muscat, Oman,' said the authors of the study.
The type of sample employed by the nine states using a sample to collect coverage data varied and included a stratified two-stage cluster sample (eight states) and a stratified one-stage cluster sample (one state).
cluster sample, and class sample; methods of selection; and problems
Update membership matrix [U.sup.(b)], and the matrix indicates the membership values of each cluster sample data belonging to the corresponding cluster prototype:
A two-stage cluster sample design was used to collect data to represent all students in grades 6-10 in each country.15 At the first stage of sampling, schools were selected with probability proportional to their reported enrolment size.15 In the second stage, classes in the selected schools were randomly selected and all students in selected classes were eligible to participate irrespective of their actual ages.15 Students self-completed the questionnaire under the supervision of trained research assistants.15
As with the detection power the repeated measures ANOVA revealed that the interaction between the method, item discrimination parameter, DIF magnitude, number of clusters, and cluster sample size was significant (p value < 0.001 and [[eta].sup.2] = 0.382).
Algorithm thought is that calculate each sample data sets the sample distribution density around; Choose the former sample distribution around the K concentration of sample points as the initial clustering center clustering; Calculation of various kinds of clusters in each sample to the other cluster sample distance, the sum of minimum value choice of the sample as the new clustering center to clustering, until the sum of all the samples to where the cluster center distance remains the same.
We have studied and analyzed the sampling method in the process of studying the IDS problem and think that the overall removal of the cluster sample is not necessarily the optimal strategy.
leprae and the efficacy of targeting contacts with preventive interventions such as chemoprophylaxis, (11) we estimated the background prevalence of leprosy in an endemic community in Bangladesh through a multistage random cluster sample of the general population.
An important component of planning experiments with clustering (whether they be multi-site or cluster randomized designs) is to determine the optimal within and between cluster sample sizes subject to a cost constraint.

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