Running average

avg.py

import random

_avg = None
_min = None
_max = None
num = []
n = 0
for i in range(10):
    k = random.randint(0, 10)
    num.append(k)
    if _avg == None:
        _min = _max = _avg = k
    else:
        if _min < k:
            _min = k
        if _max > k:
            _max = k
        _avg = (_avg + k / n) * n / (n + 1)
    n += 1
print(_avg, sum(num) / n, _min, _max)