means

#!/usr/bin/python
#
# Calculate arithmetic, geometric, harmonic means, RMS, etc.
#
# To do:
# - Python 3
#

import sys
import math

cnt = 0
invsum = 0.0
sum = 0.0
prod = 1.0
sqsum = 0.0
sqrtsum = 0.0
minval = None
maxval = None

while True:
  line = sys.stdin.readline()
  if not line:
    break
  val = float(line.strip())
  cnt += 1
  if val != 0.0:
    invsum += 1.0 / val
  sum += val
  prod *= val
  sqsum += val * val
  sqrtsum += math.sqrt(val)
  if (minval is None) or (val < minval):
    minval = val
  if (maxval is None) or (val > maxval):
    maxval = val

if invsum == 0.0:
  harm = 0.0
else:
  harm = cnt / invsum
arith = sum / cnt
try:
  geom = math.pow(prod, 1.0 / cnt)
except:
  geom = 0.0

print "min        = %f" % minval
print "max        = %f" % maxval
print "sum        = %f" % sum
print "arithmetic = %f" % arith
print "geometric  = %f" % geom
print "harmonic   = %f" % harm
print "rootmeansq = %f" % math.sqrt(sqsum / cnt)
print "sqrt       = %f" % math.pow(sqrtsum / cnt, 2.0)