Oops, try again. It looks like the standard deviation was not printed! Make sure you are printing it on its own line.

I've printed everything, yet the standard deviation doesn't show up on the console. Why is this so?

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:
         b = (average - score) ** 2
         variance = variance + b
     result = variance / len(scores)
     return result
print grades_variance(grades)

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

print print_grades(grades)
print grades_sum(grades)
print grades_average(grades)
print grades_variance(grades)
print grades_std_deviation(variance)


you have the correct idea you just need to tweak your return and variance variable,

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

because you want to return the variance to the power of a half. and then set your variance variable equal to your function with the grades as an argument.


line 36:

variance = grade_variance(grades)

you misspelled gradeS_variance, i capitalized the S to show were the typo was, but the s should be lowercase


Thanks! I made that change yet the code still had the error, so I reloaded the page and then I could pass.