Measure the asymmetry of a distribution and what it implies for analysis.
When the mean exceeds the median the distribution has a long right tail. Skewness beyond about one in absolute value usually means the mean is a poor summary and the median should be reported instead. Income and house-price data are strongly right-skewed, which is why medians rather than means are quoted in official statistics.
Skewness
Pearson’s second skewness coefficient = 3(mean − median) ÷ standard deviation
Pearson’s second skewness coefficient = 3(mean − median) ÷ standard deviation When the mean exceeds the median the distribution has a long right tail. Skewness beyond about one in absolute value usually means the mean is a poor summary and the median should be reported instead.
Income and house-price data are strongly right-skewed, which is why medians rather than means are quoted in official statistics.
This calculator takes 4 inputs: Mean, Median, Standard deviation, Sample size. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.