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deviation.go
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/
deviation.go
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package stats
import "math"
// Variance is the mean of the sum of all square deviation
func Variance(datas []float64) float64 {
avg := Mean(datas)
var ret float64 = 0
for i := 0; i < len(datas); i++ {
dist := datas[i] - avg
if dist != 0 {
ret += math.Pow(dist, 2)
}
}
if ret == 0 {
return 0.0
}
return ret / float64(len(datas))
}
// besselVariance generalize the variance for the population from a simple
// of the population
func BesselVariance(datas []float64) float64 {
avg := Mean(datas)
var ret float64 = 0
for i := 0; i < len(datas); i++ {
ret += math.Pow(datas[i]-avg, 2)
}
return ret / float64(len(datas)-1)
}
// StdDev is the standard deviation, the square root of the variance
func StdDev(datas []float64) float64 {
return math.Sqrt(Variance(datas))
}
// Bessel Standard deviation generalize the standard deviation for the population
// from a simple of the population
func BesselStdDev(datas []float64) float64 {
return math.Sqrt(BesselVariance(datas))
}
// SE (standard error) is the standard deviation of its sampling distribution
func SE(stddev float64, n int) float64 {
return stddev / math.Sqrt(float64(n))
}