Standard Deviation


#1


I get the following error message, any help would be appreciated.

Traceback (most recent call last):
File "python", line 31, in
File "python", line 29, in grades_std_deviation
TypeError: unsupported operand type(s) for ** or pow(): 'list' and 'float'


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)
    avg = sum_of_grades / float(len(grades))
    return avg

def grades_variance(grades):
    average = grades_average(grades)
    variance = 0
    for score in grades:
        sqd = (average-score)**2
        variance += sqd
        var = variance / float(len(grades))
    return var
print grades_variance(grades)

def grades_std_deviation(variance):
    return variance**0.5
    variance = grades_variance(grades)
print grades_std_deviation(variance)


#2

This line should not be indented. Remove the indent and the code will run and pass.


#3

Thank you so much! It worked