https://www.codecademy.com/courses/python-intermediate-en-7mgOa/2/1?curriculum_id=4f89dab3d788890003000096

Oops, try again. grades_variance([4, 6, 2, 0, 5, 5, 5]) returned 0.223493082 instead of the expected: 3.8367346939

```
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(s):
a=grades_average(s)
v=0
for b in s:
v=v+(a-b) ** 2
v=v/float(len(s))
return v
```