statistical-power-sample-size

To calculate sample size for biomedical study design, you must input the expected effect size, significance level (alpha), and desired statistical power to determine the required number of participants for reliable results.

Statistical power analysis requires inputs including the minimum detectable effect size, the significance level (alpha), and the target power percentage to evaluate a study's ability to detect a meaningful effect.

You need to calculate sample size and statistical power when planning a new study to ensure adequate participant numbers, or when justifying your study design to a funder to reliably detect meaningful effects.

Yes, you can assess the power of an existing psychology or public health study by evaluating whether its current sample size and effect size provide sufficient statistical power to detect the effect of interest.

The best way to justify study design sample size to a funder is by performing a formal calculation using your detectable difference, alpha level, and desired power to demonstrate adequate statistical power.