# Biostatistics calculators for medical researchers

> Free calculators for medical research: odds ratio, relative risk, NNT, sensitivity and specificity, ROC curve and AUC, sample size (proportion, two groups, survival), Cohen's kappa, intraclass correlation and Bland-Altman analysis. Each gives its result with a sentence for your manuscript and R code. Your data never leaves your browser.

Canonical: https://biostatkit.com/

- [Odds ratio calculator](https://biostatkit.com/odds-ratio): Odds ratio, 95% CI, chi-square and Fisher p-values from a 2x2 table.
- [Relative risk calculator](https://biostatkit.com/relative-risk): Relative risk, absolute and relative risk reduction with 95% CIs.
- [NNT calculator](https://biostatkit.com/nnt): Number needed to treat or harm, with a 95% CI that handles an ARR crossing zero.
- [Sample size for a proportion](https://biostatkit.com/sample-size-proportion): Participants needed to estimate a prevalence with a chosen margin of error.
- [Sample size: two means or two proportions](https://biostatkit.com/sample-size-two-groups): Participants per group to compare two groups with a chosen power.
- [Sample size: survival analysis](https://biostatkit.com/sample-size-survival): Events and participants for a log-rank comparison.
- [Sensitivity and specificity calculator](https://biostatkit.com/sensitivity-specificity): Sensitivity, specificity, PPV, NPV and likelihood ratios with 95% CIs.
- [ROC curve and AUC](https://biostatkit.com/roc-auc): Area under the curve with a 95% CI, and the best cut-off by the Youden index.
- [Cohen's kappa](https://biostatkit.com/cohens-kappa): Agreement between two raters on categories, with a 95% CI.
- [Intraclass correlation (ICC)](https://biostatkit.com/icc): Reliability of measurements by several raters, with a 95% CI.
- [Bland-Altman analysis](https://biostatkit.com/bland-altman): Bias and 95% limits of agreement between two measurement methods.

Author: TS.BS. Vũ Duy Kiên (https://www.vuduykien.com)