# 7.The Variance

#1

Oops, try again. grades_variance([5, 6, 0, 2, 9, 8, 1, 7, 2]) raised an error: float division by zero

dividing the variance by the score?

``````def grades_variance(scores):
variance = 0
for score in scores:
variance += (average - score) ** 2
variance = (variance / score)
return variance

#2

Here:

It should be:

result = variance/len(scores)

That way, you will be dividing the total variance by the number of scores rather than the score which you looped for in scores.

In full now,

``````def grades_variance(scores):
variance = 0
for score in scores:
variance += (average - score) ** 2
result = variance/len(scores)
return result

#3

Hi, from the instruction it said:

divide the total variance by the number of scores.

So, i think something wrong here:

``````    for score in scores:
variance += (average - score) ** 2
variance = (variance / score)  #this should be "scores"(list) instead of score
#and put it outside the loop since it asked to device the total variance
#and the total number of scores.
return variance``````

something like this should work.

``````    for score in scores:
variance += (average - score) ** 2
variance = (variance / len(scores))
return variance``````

Hope this help.

#4

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.