- Statistics at Square One.
- Data display and summary
- Mean and standard deviation
- Populations and samples
- Statements of probability and confidence intervals
- Differences between means: Type I and Type II errors and power
- Differences between percentages and paired alternatives
- The t-tests
- The chi-squared tests
- Exact probability test
- Rank score tests
- Correlation and regression
- Survival analysis
- Study design and choosing a statistical test

- BMJ Books
- Statistics Notes. A series of short articles on the use of statistics in the medical literature (edited by Doug Altman, Cancer Research UK, and Martin Bland, University of York).
- Topic Collections.

- Maintaining Standards: Differences between the Standard Deviation and Standard Error, and When to Use Each.
- Breaking Up is Hard to Do: The Heartbreak of Dichotomizing Continuous Data.
- What’s Under the ROC? An Introduction to Receiver Operating Characteristics Curves.

- Stats Calculator from University of Toronto's Centre for Evidence-Based Medicine. It includes the following options:
- Diagnostic Test - calculates the Sensitivity, Specificity, PPV, NPV, LR+, and LR-
- Prospective Study - calculates the Relative Risk (RR), Absolute Relative Risk (ARR), and Number Needed to Treat (NNT)
- Case-control Study - calculates the Odds Ratio (OR)
- Randomized Control Trial (RCT) - calculates the Relative Risk Reduction (RRR), ARR, and NNT

- John Pezzullo's Interactive Statistical Calculation Pages. This is a great site with lots of links to good online calculators.
- GraphPad's QuickCalcs page--another site with some very nice calculators.

- Errata and clarifications for Biostatistics: The Bare Essentials, 2nd Edition. Note that in more recent printings of the 2nd Edition than I have, some of these problems may have been fixed.
- Jerry Dallal's Little Handbook of Statistical Practice.
- Health statistics Tools of the Trade. Statistical Measurements, Data Analysis, Charts and Graphs, and Data Collection/Processing.
- Robert Wolfe's notes on confounding and effect modification.
- The "what-is" series from Evidence-based medicine.

*Last modified on 24-Oct-2008.*