Statistics
Statistical calculators for chi-square, t-test, ANOVA, correlation, power analysis, regression, and survival analysis.
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Z-Score Calculator
Calculate the z-score (standard score) for any value in a normal distribution. Find the percentile ranking and probability associated with your data point.
Confidence Interval Calculator
Calculate the confidence interval for a population mean. Determine the margin of error and range where the true population parameter likely falls.
Sample Size Calculator
Determine the required sample size for your survey or study. Calculate how many responses you need for statistically significant results.
ANOVA Calculator
Perform a one-way ANOVA (Analysis of Variance) to compare means across three groups and determine if differences are statistically significant.
Bayesian Prior Calculator
Apply Bayes' theorem to update a prior probability given test sensitivity and false positive rate. Calculate the posterior probability after a positive or negative result.
Chi-Square Test Calculator
Perform a chi-square goodness-of-fit test comparing observed and expected frequencies across four categories.
Confidence Interval Calculator
Calculate the confidence interval for a population mean using sample data. Uses z-based approximation suitable for large samples.
Correlation Calculator
Calculate the Pearson correlation coefficient (r), coefficient of determination (r²), and test significance from summary statistics.
Effect Size Calculator
Calculate Cohen's d, Hedges' g, and Glass's delta to measure the practical significance of differences between two groups.
Fisher's Exact Test Calculator
Perform Fisher's exact test on a 2x2 contingency table to determine if there is a significant association between two categorical variables.
Kruskal-Wallis Test Calculator
Perform a Kruskal-Wallis H test to compare rank distributions across multiple independent groups.
Logistic Regression Calculator
Calculate the predicted probability, odds, and odds ratio from logistic regression coefficients. Visualize the S-shaped probability curve.
Mann-Whitney U Test Calculator
Calculate the Mann-Whitney U statistic and z-score for comparing two independent groups using rank sums.
Multiple Regression Calculator
Evaluate a multiple regression model using SSR, SSE, number of predictors, and sample size. Calculate R², adjusted R², F-statistic, and model fit metrics.
Power Analysis Calculator
Calculate the required sample size for a study given the effect size, significance level, and desired statistical power.
ROC Curve Calculator
Calculate sensitivity, specificity, PPV, NPV, accuracy, F1 score, and approximate AUC from a confusion matrix (TP, FP, TN, FN).
Survival Analysis Calculator
Estimate Kaplan-Meier survival probabilities over four time periods given events and censored observations.
T-Test Calculator
Calculate the t-statistic, degrees of freedom, and approximate p-value for a one-sample t-test.