My question involves finding the range and depth of data that revolves around allowance (oh hand and deficits). For instance if you have a data sheet whose cells look like this:

Item Allowance On Hand excess/deficit
Pencil 12 7 -5
Pen 4 4 0
paper 5 4 -1

In my job I have to rely on someone providing me range and depth for meetings however recently as I have done research I am beginning to think the data I am being given is wrong so I feel its time I learned how this works and was hoping someone here could give me some perspective or lead me in the direction I need to go to learn. I would like to know how to calculate range and depth on asset requirements from data like the example I posted above. Appreciate any/all feedback.