Mean Comparison Tests
Department Salary Standardized Ranking
One-Sample t-Test Statistic
One-Sample Z-Test with Known Sigma
Standard Error of the Mean
Confidence Interval for a Difference in Means
One-Sample t-Test Reject Decision
Pooled Variance and Standard Error
Two-Sample Z-Test for a Difference in Means
Difference-in-Means Z-Test p-Value
Messages-Per-User Lift and t-Statistic
Two-Sample t-Test p-Value Bracket
Two-Sample t-Test Significance Decision
Welch-Satterthwaite Degrees of Freedom
Proportions Intervals & Effect Size
Conversion Rate and Wald Standard Error per Variant
Standardized Z-Score per Row with Outlier Flag
Wald Confidence Interval for a Conversion Rate
Agresti-Coull Interval for a Low-Volume Rate
Confidence Interval for a Mean with a Supplied t Value
Margin of Error from a Z-Critical Lookup Table
Odds Ratio from a 2x2 Contingency Table
One-Proportion Z-Test Against a Baseline
Relative Risk and Risk Difference from a 2x2 Table
Cohen's d with Pooled Standard Deviation
Confidence Interval for a Difference in Conversion Rates
Convert an Odds Ratio to Cohen's d
Experiment Analysis
Control vs Treatment Conversion Rate
Variant Click-Through Rate from Events
A/B Test Significance Decision
Pooled Conversion Proportion
Sample-Ratio-Mismatch Share Check
Standard Error of a Difference in Proportions
Two-Proportion Z-Statistic (Staged)
Daily Conversion-Rate Difference
Minimum Detectable Effect
Per-Segment Two-Proportion Z-Test
SRM Chi-Square Goodness-of-Fit
SRM Flag vs Chi-Square Critical Value
Two-Tailed P-Value from a Normal-CDF Lookup
Categorical & Chi Square Tests
Build an A/B Contingency Table
Chi-Square Degrees of Freedom
Contingency Marginal Totals
Contingency Row Proportions
A/B Test Chi-Square Significance
Chi-Square Goodness-of-Fit vs Uniform
Chi-Square Test of Independence
Expected Contingency Cell Counts
Flag Low Expected Cell Counts
Per-Cell Chi-Square Contributions
Chi-Square Homogeneity Across Groups
Chi-Square vs Critical-Value Lookup
Fisher Exact Point Probability
Phi Coefficient and Cramer's V
Yates Continuity-Corrected Chi-Square
Correlation Anova & Variance
A/B Group Sample Variance
Coefficient of Variation per Segment
Largest Month-over-Month Variance Decline
Least-Squares Slope and Intercept
Pearson Correlation Coefficient
R-Squared Coefficient of Determination
ANOVA Between and Within Sums of Squares
Correlation Significance t-Statistic
Eta-Squared Variance Explained
F-Test for Equal Variances
Levene-Style Variance Homogeneity Test
One-Way ANOVA F-Statistic
Significant Correlation Decision
Three-Metric Correlation Matrix
Nonparametric & Decision Rules
Group Median Comparison Without PERCENTILE_CONT
Sign Test on Paired Before/After Data
Critical-Value Accept/Reject Decision Lookup
Mann-Whitney U from Group Rank Sums
Rank-Biserial Effect Size from Mann-Whitney U
Threshold Percentile Position by Cohort
Wilcoxon Rank-Sum W Statistic
Bootstrap Confidence Interval for Difference in Medians
Kruskal-Wallis H Statistic
Mann-Whitney U Normal-Approximation Z-Test
Mood's Median Test Chi-Square
Permutation Test Empirical P-Value
Wilcoxon Signed-Rank W Statistic