15 lines
376 B
Python
15 lines
376 B
Python
|
G
|
import math
|
||
|
|
|
||
|
|
def mean_std(xs):
|
||
|
|
"""Return (mean, population standard deviation) of list xs."""
|
||
|
|
n = len(xs)
|
||
|
|
if n == 0:
|
||
|
|
raise ValueError("Empty list")
|
||
|
|
mean = sum(xs) / n
|
||
|
|
var = sum((x - mean) ** 2 for x in xs) / n # population variance
|
||
|
|
std = math.sqrt(var)
|
||
|
|
return (mean, std)
|
||
|
|
|
||
|
|
if __name__ == "__main__":
|
||
|
|
print(mean_std([2,4,4,4,5,5,7,9]))
|