Descriptive statistics Seventeen summary measures for one column at once Mean, median and mode Three centres of the same data, and why they disagree Standard deviation calculator Spread in the same units as your data, sample and population Variance calculator Squared spread, in both the sample and population forms Quartiles and percentiles Where your data sits, from P5 to P99 Five-number summary Minimum, Q1, median, Q3 and maximum in one line Histogram builder The shape of a distribution, with bin width chosen for you Box plot builder Five numbers and the outliers, drawn compactly Outlier detection Two independent rules, and the rows they disagree about Z-score calculator Every value expressed in standard deviations from the mean Pearson correlation How strongly two columns move together, with a p-value Spearman correlation Rank correlation — robust to outliers and curved relationships Correlation matrix Every numeric column against every other, in one table Linear regression The line through your points, with its equation and R² Moving average Smoothing that reveals the trend and hides the noise Confidence interval for the mean The range the true average probably sits in Student's t-test Whether two groups really differ, with an effect size Chi-square test Whether two categorical variables are related Normality check Whether your data is normal enough for the usual formulas Frequency table How often each distinct value appears, with cumulative shares Pareto and ABC analysis Which few items produce most of the result Coefficient of variation Relative spread, comparable across different units Data normalisation Three ways to put a column on a common scale Weighted average An average where some rows count more than others Geometric and harmonic mean The right averages for growth rates and for speeds Data quality report Missing values, duplicates and column types, before you analyse anything
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