8/9 Standard Deviation


#1


I'm stumped. I've looked at this 100X and I'm sure I'm missing something simple. Just can't pinpoint
it. Here's the error I'm getting:

Oops, try again. grades_std_deviation(7.25) returned 18.2776094147 instead of the expected: 2.6925824036

Here's the code

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 / float(len(grades))
    return average

def grades_variance(scores):
    average = grades_average(scores)
    variance = 0
    for score in scores:
        variance += (average - score) ** 2
    return variance / len(scores)

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

print grades_std_deviation(variance)


#2

Hi here

def grades_std_deviation(vairance)

you wrote vairance instead of variance


#3

Hahaha! I knew I was exposing my stupidity by putting this out there, but I was sick of looking at it.
bad brain....bad.

Thanks for the help.