Standard library · Numbers and collections

stats

Descriptive statistics over a list of numbers: mean, median, variance, standard deviation and percentiles.

import stats

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Functions

The stats package works on a Vector<f64> and never changes it. Variance and standard deviation come in two forms: the ordinary one for when the data is a sample of a larger population, dividing by n−1, and the "population" one for when you have the whole population, dividing by n.

Functions

`Sum`

func Sum(v: Vector<f64>): f64

The sum of all the numbers.

stats-Mean.salam

import stats

func main:
    mut scores := Vector {} as Vector<f64>
    defer scores.free()
    each s in [12.0, 18.0, 15.0, 19.0, 11.0]:
        scores.push(s)
    end
    println stats.Sum(scores), stats.Mean(scores), stats.Median(scores)
    println stats.Min(scores), stats.Max(scores)
    println stats.Variance(scores), stats.PopVariance(scores)
    println stats.Stdev(scores), stats.PopStdev(scores)
    println stats.Geomean(scores), stats.Percentile(scores, 90.0)
end

Output75 15 15 11 19 12.5 10 3.5355339059327378 3.1622776601683795 14.660144778355681 18.6

`Mean`

func Mean(v: Vector<f64>): f64

The arithmetic mean.

The example for this item is shown with the ones above: stats-Mean.salam

`Min`

func Min(v: Vector<f64>): f64

The smallest number.

The example for this item is shown with the ones above: stats-Mean.salam

`Max`

func Max(v: Vector<f64>): f64

The largest number.

The example for this item is shown with the ones above: stats-Mean.salam

`Median`

func Median(v: Vector<f64>): f64

The middle number after sorting, or the mean of the middle two when there is an even count. It stands up to outliers better than the mean.

The example for this item is shown with the ones above: stats-Mean.salam

`Variance`

func Variance(v: Vector<f64>): f64

The sample variance, dividing by n−1.

The example for this item is shown with the ones above: stats-Mean.salam

`PopVariance`

func PopVariance(v: Vector<f64>): f64

The population variance, dividing by n.

The example for this item is shown with the ones above: stats-Mean.salam

`Stdev`

func Stdev(v: Vector<f64>): f64

The sample standard deviation, the square root of the sample variance.

The example for this item is shown with the ones above: stats-Mean.salam

`PopStdev`

func PopStdev(v: Vector<f64>): f64

The population standard deviation.

The example for this item is shown with the ones above: stats-Mean.salam

`Geomean`

func Geomean(v: Vector<f64>): f64

The geometric mean, which suits growth rates and ratios better than the arithmetic mean. Every number has to be positive.

The example for this item is shown with the ones above: stats-Mean.salam

`Percentile`

func Percentile(v: Vector<f64>, p: f64): f64

The pth percentile, with p between zero and a hundred; the 90th percentile, for instance, is the value 90 per cent of the data falls below.

The example for this item is shown with the ones above: stats-Mean.salam