Statistics (24 tools)
Distributions, hypothesis tests, confidence intervals, regression and sample size
📊Normal Distribution CalculatorNormal probabilities and Z scores.📏Confidence Interval CalculatorConfidence intervals for a mean.🎲Sample Size CalculatorSurvey sample size and margin.𝑧Z-Score CalculatorZ scores, percentiles and critical values.📐T-Test CalculatorOne- and two-sample t tests.📉Correlation & RegressionCorrelation and regression.📊One-Sample t-Test CalculatorTest whether a sample mean differs from a hypothesised value, reporting t, df and the critical-value verdict.📊Two-Sample t-Test CalculatorCompare the means of two independent samples with the difference, Welch standard error and t.📊Chi-Square Test CalculatorEnter the four counts of a 2×2 table to get chi-square, the verdict and Cramér V.📊Pearson Correlation CalculatorPearson r, coefficient of determination and regression slope from two series.📊Simple Linear Regression CalculatorFit a least-squares line to two series, reporting slope, intercept, R² and a prediction.📊Mean Confidence Interval CalculatorConfidence interval and margin of error for a mean using the large-sample approximation.📊Sample Size for a Mean CalculatorRequired sample size from expected standard deviation, margin of error and confidence level.📊Odds Ratio and Relative Risk CalculatorOdds ratio, relative risk, absolute risk difference and NNT from a 2×2 table.📊Mean Median Mode CalculatorMean, median, mode, quartiles and range in one pass.📐Proportion Confidence Interval95% confidence interval and standard error for a proportion.🎯Sample Size for a ProportionSample size needed from expected proportion, margin of error and confidence level.📈Z-Score to PercentileConvert a z-score into its percentile, two-tailed p and critical-value verdict.🔍Outlier DetectionFlag outliers with both the IQR and z-score methods, reporting the bounds.⚖Weighted AverageWeighted mean from values and weights, compared with the simple mean.📉Coefficient of VariationMean, standard deviation and coefficient of variation for comparing dispersion across units.📊sample size CalculatorSample size for estimating a mean from confidence level, margin of error and standard deviation.📈effect size CalculatorCohen's d and a sample-size reference from two means and the pooled standard deviation.🤝kappa agreement CalculatorCohen's kappa and its agreement strength from a 2×2 table.