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#!/usr/bin/awk -f
### mean.awk
# calculate mean average of serialized input
BEGIN {
OFS = FS
#sign = "[+-]?"
#decimal = "[0-9]+[.]?[0-9]*"
#fraction = "[.][0-9]*"
#exponent = "([Ee]" "[+-]?" "[0-9]+)?"
number = "^[+-]?([0-9]+[.]?[0-9]*|[.][0-9]*)([Ee][+-]?[0-9]+)?$"
}
# Welford's 'online' algorithm for variance
NF {
for (n=1; n<=NF; n++) {
if ($n ~ number) {
count += 1
(count == 1 || $n < min) ? min = $n : min = min
(count == 1 || $n > max) ? max = $n : max = max
range = max - min
delta0 = $n - mean
mean += delta0/count
delta1 = $n - mean
M2 += delta0*delta1
(count > 1) ? var = M2/(count - 1) : var = "nan"
}
}
}
END {
print "mean", "std_err", "std_dev", "range", "min", "max", "total", "count"
print mean, sqrt(var/count), sqrt(var), range, min, max, (mean*count), count
}
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