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/lib/mlbackend/php/phpml/src/Phpml/Math/Statistic/ -> Variance.php (source)

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Defines 1 class

Variance:: (1 method):
  population()


Class: Variance  - X-Ref

In probability theory and statistics, variance is the expectation of the squared deviation of a random variable from its mean.
Informally, it measures how far a set of (random) numbers are spread out from their average value
https://en.wikipedia.org/wiki/Variance

population(array $population)   X-Ref
Population variance
Use when all possible observations of the system are present.
If used with a subset of data (sample variance), it will be a biased variance.

∑⟮xᵢ - μ⟯²
σ² = ----------
N