Check out the standard deviation in Go.
It is meant to be simple and easy to read, hopefully it is.
import (
"fmt"
"github.com/antonlindstrom/gostddev"
)
func MyStdDev() {
set := float64{1,2,3,4,5}
fmt.Printf("%f\n", gostddev.StdDev(set))
// Prints 1.41421
}