Problem:

Compute the mean of ${3 \sqrt{5}, 3 \sqrt{5}, -4 \sqrt{5}, 0, 3 \sqrt{5}, 2 \sqrt{5}, -\sqrt{5}}$.

import math

from statistics import mean
values = 3*math.sqrt(5), 3*math.sqrt(5), -4*math.sqrt(5), 0, 3*math.sqrt(5), 2*math.sqrt(5), -math.sqrt(5)
print(mean(values))
