Ruby needs a solid, beautiful stats library. We're here to build just that. This is a rapidly moving work in progress.

• Normal distribution - PDF & CDF
• Chi square distribution - PDF
• T distribution - PDF & CDF
• F distribution - PDF & CDF

• Mean, arithmetic
• Mean, geometric
• Median
• Mode
• Variance
• Standard deviation
• Standard error of the mean (for samples only)
• Relative standard error of the mean (for samples only)
• Coefficient of variation

• Chi square, one-sided
• T-test, single sample
• T-test, two-sample
• T-test, repeated measures
• Wilcoxon rank sum test
• Wilcoxon signed rank test
• Median test
• Kruskall-Wallis H test
• Friedman test
• ANOVA, one way
• Factorial ANOVA, two-way
• Factorial ANOVA, three-way
• ANOVA, repeated measures
• MANOVA
• ANCOVA

• Linear regression
• Multiple linear regression
• Pearson's correlation
• Spearman correlation

• Basic assumption framework
• Confidence intervals (general idea)
• Basic data structures
• Significance methods on data structures

• How to choose the right statistical test
• Wilkinson's Statistics Quiz (RTF)
• Assessing the reliability of statistical software
  • Part 1
  • Part 2