Descriptive Statistics
Calculate mean, median, mode, standard deviation, variance, range, IQR, skewness, and kurtosis for your dataset.
Frequency Distribution
Generate frequency tables with counts and percentages for categorical data. Perfect for demographic tables.
Normality Test
Test if your data follows a normal distribution using Shapiro-Wilk test. Essential before parametric tests.
Independent t-Test
Compare means between two independent groups. Includes Welch's t-test, confidence intervals, and Cohen's d effect size.
Paired t-Test
Analyze before-after or matched-pairs data. Tests whether the mean difference is significantly different from zero.
Chi-Square Test
Test association between categorical variables. Automatically switches to Fisher's exact test for small samples.
One-Way ANOVA
Compare means across three or more independent groups. Includes F-statistic, p-value, and effect size (ฮทยฒ).
Mann-Whitney U Test
Non-parametric alternative to independent t-test. Use when normality assumption is violated or data is ordinal.
Wilcoxon Signed-Rank
Non-parametric alternative to paired t-test for matched or repeated measures when data isn't normally distributed.
Kruskal-Wallis Test
Non-parametric alternative to one-way ANOVA. Compare distributions across 3+ independent groups.
Pearson Correlation
Measure linear relationship between two continuous variables. Includes r, p-value, 95% CI, and interpretation.
Spearman Correlation
Non-parametric correlation for monotonic relationships or ordinal data. Robust to outliers and non-normality.
Simple Linear Regression
Model relationship between predictor and outcome. Get slope, intercept, Rยฒ, p-values, and regression equation.
2ร2 Table (RR, OR, NNT)
Calculate Relative Risk, Odds Ratio, Risk Difference, and NNT/NNH from cohort or case-control studies.
Diagnostic Test Accuracy
Calculate sensitivity, specificity, PPV, NPV, likelihood ratios, and accuracy from diagnostic test results.
Incidence & Prevalence
Calculate disease incidence rates and prevalence from population data. Supports different time periods.
Attributable Risk
Calculate attributable risk, attributable risk percent, and population attributable risk from exposure data.
Sample Size: Single Proportion
Determine sample size needed for estimating a single proportion with specified precision and confidence level.
Sample Size: Two Proportions
Calculate sample size for comparing proportions between two groups. Specify alpha, power, and expected proportions.
Sample Size: Two Means
Determine sample size for comparing means between groups. Input expected means, SD, alpha, and desired power.
Sample Size: Correlation
Calculate required sample size to detect a correlation of a given magnitude with specified power and alpha.
Power Calculator
Post-hoc power analysis. Calculate statistical power given sample size, effect size, and significance level.