Types of Measure

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. nin(1xi)\frac{n}{\sum_i^n(\frac{1}{x{i}})} , where i=1,2,...ni=1,2,...n and nn is the number of items in the dataset xx .

  • Geometric Mean is the n-th root of the product of all nn elements xix_i in a dataset xx. inxin\sqrt[n]{\prod_i^n x_{i}} , where i=1,2,...ni=1,2,...n and nn is the number of items in the dataset xx .

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.