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    stats_variance

    (PECL stats >= 1.0.0)

    stats_variance — Returns the variance

    説明

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

    Returns the variance of the values in a.

    パラメータ

    a

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

    sample

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

    戻り値

    Returns the variance on success; false on failure.

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    User Contributed Notes 1 note

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    -9
    Anonymous
    15 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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