(PECL stats >= 1.0.0)

stats_varianceReturns the variance


stats_variance(array $a, bool $sample = false): float

Returns the variance of the values in a.



The array of data to find the standard deviation for. Note that all values of the array will be cast to float.


Indicates if a represents a sample of the population; defaults to false.

Return Values

Returns the variance on success; false on failure.

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User Contributed Notes 1 note

14 years ago
This will return surprising values for most users, since the default of sample=false is rather unusual when speaking about variance.

Point is:
When using stats_variance($foo,TRUE) the sum is divided by n-1 while the default just divides it by n. So when you expect your variance to be lower you probable wanted to divide by n-1, therefore should set the second parameter =TRUE.
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