hi i need help figuring out how to get my program to calculate standard deviation. this is what i've done so far:

import math
import sys

lines = sys.stdin.readlines()
sample_number = 0
time_seconds = 0
time_list = []

for line in lines:
time = line.split('\t')
f2 = time[1].strip('\n')

if time[0]!= '-1':
time_seconds += float(f2)
sample_number += 1

print sample_number, 'data records'
print 'Mean is ', time_seconds/sample_number
print 'Standard deviation is ',

Any help or ideas would be greatly appreciated, thanks!

Your code does not make much sense, but you could google for standard deviation and learn.