Sample sizeCombined cohortCensoringLength-biasMeta-analysisThe determination of the sample size is key in the design of a cohort study when requiring a preset statistical power for comparing time to event outcomes of two groups. In complex survival analysis study designs, the time to event data ...
Adjusting for losses to follow-up in sample size determination for cohort studies J Chron Dis (1979) C. Kilkenny et al. Survey of the quality of experimental design, statistical analysis and reporting of research using animals PLoS One (2009) M.F.W. Festing On determining sample size in ex...
In this study, based on the GEE approach, we present closed-form sample size calculation that is applicable to both closed-cohort and cross-sectional stepped wedge trials. Importantly, the proposed method is flexible to accommodate design issues routinely encountered in pragmatic trials, such as ...
This technical note introduces a data-driven sample size determination for metabolic phenotyping studies. Starting from nuclear magnetic resonance (NMR) spectra belonging to a small cohort, metabolic NMR variables are identified by the statistical recoupling of variables (SRV) procedure. A larger data ...
Considering the distribution of the test-negative design data, the score test approach based on multinomial distribution can be an alternative for the sample size determination. Finally, we have framed the problem as a hypothesis test to assess whether VE > 0% or relative VE > 0% (...
formulae, might be useful for retrospectively computing power once a trial has commenced (and thus the size has been determined), and will also be useful in those limited number of studies for which the trial sample size is indeed completely fixed (for example within a cohort study) [9, ...
摘要: Provides an introduction to sampling, determination of sample size, and selection of the actual sample. Focus on concepts, general sources, and sampling software; Identification of sources that provide formulae and procedures for determining sample size....
Determining Sample Size: Balancing Power, Precision, and Practicality Sample size determination is an important and often difficult step in planning an empirical study. From a statistical perspective, sample size depends on the following factors: type of analysis to be performed, desired precision of ...
* II. Determination of sample size: Qualitative studies There are no fixed rules for sample size in qualitative research. The size of the sample depends: on what one is trying to find out from what different respondents or perspectives one tries to find that out for example, the number of ...
Sample size calculations belong to the routine steps in the design of studies for drug development. The importance of the determination of the appropriate sample size for clinical studies is emphasized in the ICH Guidelines: " The number of subjects in a clinical trial should always be large enou...