Pretty sure the problem here will be something like the other 2 posts I've made, the shell is testing other numbers but the call is throwing something off and I don't understand what it is.

The error I get is below, the return the correct one for the actual grades list.

Oops, try again. grades_std_deviation(12.6666666667) returned 18.2776094147 instead of the expected: 3.559026084

```
grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]
def print_scores(scores):
for grade in scores:
print grade
def scores_sum(scores):
total = 0
for grade in scores:
total += grade
print "Sum: ",total
return total
def scores_average(scores):
sum_of_scores = scores_sum(scores)
average = sum_of_scores / float(len(scores))
print "Average: ",average
return average
def scores_variance(scores):
num = len(scores)
average = scores_average(scores)
var = 0
for score in scores:
var += float(average - score) ** 2
print "Variance: ",var/num
return var/num
def scores_std_deviation(variance):
return variance ** 0.5
variance = scores_variance(grades)
print scores_std_deviation(variance)
```