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.
stats_variance
(PECL stats >= 1.0.0)
stats_variance — Returns the population variance
설명
float stats_variance
( array
$a
[, bool $sample = false
] )Warning
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인수
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a -
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sample -
반환값
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Anonymous ¶
15 years ago
