Topics

Sample Size Calculators
Use these free online calculators to estimate the needed sample size for a straightforward one- or two-group study. The methods referenced in…
Power and Sample Size Concepts
These resources explain the concepts of power and sample size and what they depend on.
Finding and Working with a Biostatistician
These resources provide guidance on how to find and work with a biostatistician.  
Data Collection and Management
These resources provide guidance on collecting and managing study data.  
Hypothesis Tests and P-Values
These resources explain the concepts involved in carrying out hypothesis tests and correctly interpreting the resulting p-values.  
Screening and Diagnostic Tests
These resources explain the key concepts involved in designing, evaluating and interpreting the results of diagnostic tests: sensitivity, specificity…
Multiple Testing
These resources explain what multiple testing is, why it is problematic, and how to recognize and control for it.
Non-Parametric Methods
These resources describe commonly used non-parametric methods and their advantages and disadvantages.
Post-hoc Power Analyses
These resources explain what post-hoc power analyses are and why they aren’t useful in most cases.
Study Designs
These resources provide an overview of the main observational and experimental study designs and the advantages and limitations of each.
Collection of Race and Ethnicity Data
These resources describe considerations and best practices for collecting and reporting data on race or ethnicity in a study.
Basic Statistical Tests
These resources describe t-tests and chi-squared tests: what the tests are for, when to use them, and how to interpret the results.