```
grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]
def print_grades(grades_input):
for grade in grades_input:
print grade
def grades_sum(scores):
total = 0
for score in scores:
total += score
return total
def grades_average(grades_input):
sum_of_grades = grades_sum(grades_input)
average = sum_of_grades / float(len(grades_input))
return average
def grades_variance(scores):
average = grades_average(scores)
variance = 0
for score in scores:
variance += (average - score) ** 2
result = variance / float(len(scores))
return result
def grades_std_deviation(variance):
return variance ** 0,5
variance = grades_variance(grades)
print variance
print grades_std_deviation(variance)
```

So this is my code, i have now looked over it for 10 minutes and tried out multiple thingsâ€¦

â€śgrades_std_deviation(6.6875) returned (1.0, 5) instead of the expected: 2.5860201082â€ť is the error message that i get with the code from above. when i try to test grades_std_deviation with a number like 123 or something it always delivers a list (1 , 5).

The pproblem is probably pretty stupid and i will be ashamed, but i give up after comparing my code to others and checking over and overâ€¦