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2015
One of the questions most frequently asked of a statistician is: How big should the sample be? Managers are anxious to obtain an answer to this fundamental question during the planning phase of the survey since it impacts directly on operational considerations such as the number of interviewers required.
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One of the questions most frequently asked of a statistician is: How big should the sample be? Managers are anxious to obtain an answer to this fundamental question during the planning phase of the survey since it impacts directly on operational considerations such as the number of interviewers required.
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Sample size determination for the fluctuation experiment
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 2017The Luria-Delbrück fluctuation experiment protocol is increasingly employed to determine microbial mutation rates in the laboratory. An important question raised at the planning stage is "How many cultures are needed?" For over 70 years sample sizes have been determined either by intuition or by following published examples where sample sizes were ...
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On the use of a pilot sample for sample size determination
Statistics in Medicine, 1995AbstractTo compute the sample size needed to achieve the planned power for a t‐test, one needs an estimate of the population standard deviation δ. If one uses the sample standard deviation from a small pilot study as an estimate of δ, it is quite likely that the actual power for the planned study will be less than the planned power.
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A Review of Software for Sample Size Determination
Evaluation & the Health Professions, 2009The size of a sample is an important element in determining the statistical precision with which population values can be estimated. This article identifies and describes free and commercial programs for sample size determination. Programs are categorized as follows: (a) multiple procedure for sample size determination; (b) single procedure for sample
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Sample size determination in epidemiologic studies
Statistical Methods in Medical Research, 1995Sample size determination is an important issue in epidemiologic studies. Standard methods for determining sample size in cohort and case-control studies have generally been restricted to dichotomous disease and exposure variables and discrete confounding variables, and are based on simplifying assumptions that could often be unrealistic.
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, 2008