#!/usr/bin/perl -s

$^W = $w;

while(<>) {
    /\d/ or next;
    $n++;
    $i = $a ? abs($_) : 0+$_;
    $s += $i;
    $s2 += $i**2;
    push @a, $i;
    print if $echo;
}

$s /= $n;
$s2 /= $n;
if($q) {
    if($n>1) {
        printf "%f +/- %f\n", $s, sqrt($s2-$s**2)*1.645/sqrt($n-1);
    } else {
        printf "%f\n", $s;
    }
} else {
    printf "samples: %d\nmean%s: %f\nmedian: %f\nrms: %f\nstddev: %f\n",
        $n, $a ? " abs" : "", $s, (sort {$a<=>$b} @a)[$#a/2], sqrt($s2), sqrt($s2-$s**2);
    printf "90%: +/- %f\n", sqrt($s2-$s**2)*1.645/sqrt($n-1) if $n>1;
}