Question

Code for calculating standard deviationin in python

Answer 1

Answer:

Suppose your data is in the list variable X.

To avoid problems, you should make sure the values are 'float' type, not 'int'.

>>> X = [ float(x) for x in X ]

The number of values is

>>> n = len(X)

The sum of the values is

>>> sum(X)

The mean is

>>> mean = sum(X) / n

The sum of the squares of the values is

>>> ssq = sum(x**2 for x in X)

The variance is the mean of these minus the square of the mean:

>>> var = ssq / n  -  mean**2

The standard deviation is the square root of the variance

>>> sd = pow(var, 0.5)

All in one step:

>>> sd = pow(sum(x**2 for x in X)/len(X) - (sum(X)/len(X))**2 , 0.5)