Central Tendency tells you about the centers of the data. Useful measures include the mean (Weighted Mean, Harmonic Mean, Geometrical Mean), median, and mode (Mode, Multimode).
Harmonic Mean is the reciprocal of the arithmetic mean of the reciprocals. , where and is the number of items in the dataset .
Geometric Mean is the
n-th root of the product of all elements in a dataset .
, where and is the number of items in the dataset .
Variability tells you about the spread of the data. Useful measures include variance, Standard deviation, Skewness, Percentile, and Range.
Correlation or Joint Variability tells you about the relation between a pair of variables in a dataset. Useful measures include covariance and the correlation coefficient.