RosettaCodeData/Task/Statistics-Basic/Zkl/statistics-basic-1.zkl

fcn mean(ns)  { ns.sum(0.0)/ns.len() }
fcn stdDev(ns){
   m:=mean(ns); (ns.reduce('wrap(p,n){ x:=(n-m); p+x*x },0.0)/ns.len()).sqrt()
}