cluster sample


Also found in: Medical.

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.
References in periodicals archive ?
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).
A two-stage cluster sample design was used to collect data to represent all students in grades 6-10 in each country.
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.
A means of determining the sample size required for a cluster sample with sufficient power is to incorporate the design effect in the calculations.
The margin of error reflects the influence of using a multi-stage cluster sample and data weighting.
A two-stage stratified cluster sample design was used (Joncas, 2008); schools were selected during the first stage of sampling and then classrooms within schools were sampled during the second stage.
Respondents were randomly selected from a cluster sample provided by Survey Sampling International.
The first of these studies, published in 2004, used a cluster sample survey of households in Iraq to develop an estimate ranging from 8,000 to 194,000 civilian casualties due to violent deaths since the start of the war.
Researchers at Johns Hopkins released a massive, rigorous cluster sample survey of Iraqi casualties in October, which found, between 2003 and 2006, an estimated 654,965 "excess deaths"--that is, deaths above and beyond the country's prewar mortality rate.

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