Table 1 below shows that if the groups are of equal size (a 1:1 ratio), then the power is 0.87. The study has an 87% chance of detecting a true difference in birth weight of 250g. The power reduces as ...

Course TopicsPower analyses and sample size calculations are important parts of many research projects. Often, before data are even collected, it is necessary to calculate and justify the required ...

Summary Choosing the proper sample size for an investigation is one of the crucial jobs required of a statistician. Regardless of whether the statistician is deciding the number of patients to select ...

In order to achieve 80% power to detect, in a single study, the most probable true effects as indicated by the meta-analysis, a sample size of 134 animals would be required for the water maze ...

Recently, Cheung 20 presented a closed-form formula for sample size calculation, in which a nonparametric optimal design 21 was exploited and the accuracy index of the CRM design was derived ...