I was wondering how the data should be normalized in the programming assignment.

In a previous post, you (Regev :P) answered "Yes, but as before, this means to the scale the data so the the mean is 0 and the std is 1" but

in the exercise it says "Normalize the input vectors such that all attributes are in [−1, 1]".

Scaling the data so that the mean is 0 and the std is 1 doesn't promise attributes in [-1,1].

What should we do? Normalize the mean and std? or just scale the data to be within the limits,

(data - min(data)) / (max(data) - min(data)) * 2 - 1

for example..?