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#!/usr/bin/env python
# Copyright 2008 Nanorex, Inc. See LICENSE file for details.
"""
Reads a sequence of numbers from stdin, and calculates the mean and
standard deviation.
"""
import sys
from math import sqrt
def main():
numbers = []
line = sys.stdin.readline()
while (line):
numbers.append(float(line))
line = sys.stdin.readline()
samples = len(numbers)
mean = sum(numbers) / samples
if (samples < 2):
variance = 0
else:
sampleVariance = map(lambda x: (x - mean) * (x - mean), numbers)
variance = sum(sampleVariance) / (samples - 1)
print "samples: %d, mean: %f, standardDeviation: %f" % (samples, mean, sqrt(variance))
if (__name__ == '__main__'):
main()
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