74 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Statistical notes for clinical researchers: Sample size calculation 1. Comparison of two...

Sample-size determination is often an important step in planning a statistical study—and it is usually a difficult one. Among the important hurdles to be surpassed, one must obtain an estimate of one or more error variances, and specify an effect size of importance. There is the temptation to take some shortcuts. This paper offers some suggestions for successful and meaningful sample-size deter...

UNLABELLED Calculation of the appropriate sample size in planning microarray studies is important because sample collection can be expensive and time-consuming. Sample-size calculation is also a challenging issue for microarray studies because the number of genes is far larger than the number of samples so that traditional methods of sample-size calculation cannot be directly applied. To help i...

BACKGROUND AND OBJECTIVES School-based nutrition education has been widely implemented in recent years to fight the increasing prevalence of childhood obesity in China. METHODS AND STUDY DESIGN A comprehensive literature search was performed using six databases to identify studies of school-based nutrition education interventions in China. The methodological quality and the risk of bias of se...