Python program to find the variance

So here is the code:

def variance(X):
    mean = sum(X)/len(X)
    tot = 0.0
    for x in X:
        tot = tot + (x - mean)**2
    return tot/len(X)

# main code
#  a simple data-set 
sample = [1, 2, 3, 4, 5] 
print("variance of the sample is: ", variance(sample))

sample = [1, 2, 3, -4, -5] 
print("variance of the sample is: ", variance(sample))

sample = [10, -20, 30, -40, 50] 
print("variance of the sample is: ", variance(sample))

Output:

ariance of the sample is:  2.0
variance of the sample is:  10.64
variance of the sample is:  1064.0