Codecademy: Standard Deviation

#sample solution


grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]

def print_grades(grades):
    for grade in grades:
        print grade

def grades_sum(grades):
    total = 0
    for grade in grades:
        total += grade
    return total
   
def grades_average(grades):
    sum_of_grades = grades_sum(grades)
    average = sum_of_grades / len(grades)
    return average

def grades_variance(grades,average):
variance = 0
for grade in grades:
variance = variance + ((average - grade)**2)
return variance

print grades_variance(grades,grades_average(grades))

def grades_std_deviation(variance):
return variance**0.5

print grades_std_deviation(grades_variance(grades,grades_average(grades)))