Review Exercise

If I use the following code:

def grades_std_deviation(variance):

result = variance ** 0.5

return result

...taking the variance as an input, then the standard deviation function behaves fine. But if I try to make the standard deviation function take an input of grades like all the other functions in the exercise:

def grades_std_deviation(grades):

result = grades_variance(grades) ** 0.5

return result

...it tells me a float is not iterable. I don't understand what I'm iterating here, or how this function is different than the variance function or average function, which both take inputs of grades and call a previously defined function.

I suppose whatever the reason is why they designed the exercise to just take variance as an input, but I'd like to better understand the reasoning and the problem.

I hoped it would work.

`Replace this line with your code.`