# 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.$\frac{n}{\sum_i^n(\frac{1}{x{i}})}$, where$i=1,2,...n$and$n$is the number of items in the dataset$x$.**Geometric Mean**is the`n-th`

root of the product of all$n$elements$x_i$*in a dataset*$x$*.*$\sqrt[n]{\prod_i^n x_{i}}$, where$i=1,2,...n$and$n$is the number of items in the dataset$x$.

**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.

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