In this case the range is actually equal to 0 < x < 4 (those should be less than-or-equal signs but not sure how to do them on here), and the midpoint of that range is 2. So use 2.
I understand that when finding the mean for grouped data,
with class interval, e.g. , we use the midpoint of the interval, then multiply by frequency, and so on...
My question is this,
If x is discrete, for the range , then x takes values 0, 1, 2, 3, 4. Should we choose 2 for the midpoint? or 2.5?
Which one better?