import math


def GetStandardDeviation(vals_l, mean):
    """ We get the Standard Deviation from a list of values

    Args:
        vals_l: (list<int/float>) The values.
        mean: (float) The mean of vals_l (sum/length)

    """


    sum_deviations_squared = 0

    for x in vals_l:
        sum_deviations_squared += (x - mean)**2

    return math.sqrt(float(sum_deviations_squared)/float(len(vals_l)))