P–03 Products
Validated against the textbook values.
Calculators & Tools — sample size, power, and the everyday statistics of study planning, checked against the references.
What's inside
- Sample size: two proportions, two means, one proportion
- Power: recover achieved power from n and effect size
- Design extras: allocation ratios, one- and two-sided tests, dropout inflation
- The formula shown with every result — no black boxes
Why it matters
An underpowered study is an expensive way to produce nothing. These calculators make the power conversation happen early, with numbers a statistician will sign off on.
How you use them
Free in the browser. Inside the workspace, results flow straight into your protocol's sample-size section.
Your next study could move like this.