Statistics, calculated clearly.
Accurate calculators and reference tables with the formulas, worked steps, and plain explanations behind every result — built for students, researchers, and analysts.
Calculators
View all →Standard Deviation
→Sample & population standard deviation with steps.
Variance
→Population & sample variance with steps.
Mean, Median, Mode
→The core measures of central tendency, instantly.
Coefficient of Variation
→Compute %CV from data or mean and standard deviation.
Percentile & IQR
→Quartiles, IQR, percentiles, and a box plot.
Skewness
→Measure distribution asymmetry.
Kurtosis
→Excess kurtosis (sample & population).
Linear Regression
→OLS line, slope, intercept, and R².
Correlation Coefficient
→Pearson r for paired data, with a scatter plot.
P-Value
→Find p-values from a test statistic, with interpretation.
Confidence Interval
→CI for a mean using the z- or t-distribution.
Hypothesis Test
→One- and two-tailed tests with a decision.
Difference in Means
→Compare two population means.
Sample Size
→Required sample size for a survey or study.
Chi-Square
→Goodness-of-fit and independence tests.
One-Way ANOVA
→Compare the means of three or more groups.
Z-Score
→Convert a value to a z-score and percentile.
Normal Distribution
→Probabilities and percentiles for any normal distribution.
Probability
→Probability of two events (AND, OR, conditional).
Combinations & Permutations
→nCr, nPr, and factorials.