stats_stat_powersum
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
- a
-
- sample
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반환값
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User Contributed Notesstats_variance
Anonymous
27-Feb-2009 09:43
27-Feb-2009 09:43