Mean, median, mode and stddev calculation in Python 3

mean_median_mode_stddev.py

sample = [5, 3, 1, 2, 4]
n = len(sample)
mean = sum(sample)/n
median = (sample[n//2 - (n + 1)%2] + sample[n//2])/2
stddev = (sum((e - mean)**2 for e in sample)/n)**0.5
cnt = {}
for e in sample:
    cnt[e] = cnt.get(e, 0)
    cnt[e] += 1   
mode = sorted(cnt.keys(), key=lambda e: (cnt[e], -e))[-1]

call 'sample.sort()' before evaluating 'median = (sample[n//2 - (n + 1)%2] + sample[n//2])/2'

mode = max(set(sample), key= sample .count)