Sentence examples for deriving a sample size from inspiring English sources

In deriving a sample size for patient subgroups we extrapolated from the PECARN data as it is the only CDR which differentiates between children aged less than two years and children aged two years and older [ 17].

Calculations derived a sample size of 17 children in each group to yield 80% power (with alfa.05) in detecting a reduction of 2 point in MOPS.

Assuming the Cox proportional hazards model, Hsieh and Lavori (2000) derived a sample size formula in which the variance of a continuous variable σ satisfies where Δ is the hazard ratio associated with one unit of increase in marker values.

Each equation (no. 1 12) were derived from a sample size of n = 50 randomly selected trees from five BWI plots.

Missing data were removed from the analysis as displayed in Table  2.> -wrap-foot> *This weighted n is derived from a sample size of 2745, of which 2272 (82.8%) were non-rural residents and 473 (17.2%) rural residents.

The number of animals used was derived from a sample size calculation based on historical airway function data from two previous studies using the change in PC30 (the intravenous histamine dose required to generate a 30% increase in lung resistance [RL] above baseline) induced by double antigen challenge.

Given the multiplicity of analyses employed in the development of a new instrument it is difficult to derive a priori sample size estimates.

Studies need to focus on preschool children and draw on large populations to derive a meaningful sample size.

More recently, MacCallum and colleagues [ 32] took a unique approach to the problem and used factor analytic theory [ 33] to show it may not be possible to derive a minimum sample size that is appropriate in all situations.

Frison and Pocock[ 5] have derived a generalized sample size equation that can be used to assess power for ANCOVA where baseline measures are taken before treatment: p is the number of baseline measures; subscripts pre, post and mix refer, respectively, to the mean correlations within baseline measurements, within follow-up measurements and between baseline and follow-up measures.

Here we derive a similar result, showing that a sample size of about N/r is required to maintain equivalent power to detect a deviation from a multiplicative model.