Is it presumptious?

[quietman]

To ask what the average amount and range of funding is for the other admits in the program I'm considering?

[TakeruK]

I think this is a bad question to ask. I can't think of a good reason for a candidate to ask this. It sounds like you are trying to ensure you are earning more than your peers or something, which is not the impression you want to make. It's okay to talk about money, but keep the topic focussed on you, not the other students.

Maybe you have better intentions though, and maybe you want to know if your stipend is enough to live on? If so, then I would recommend approaching this another way. Ask if you could talk to some students if you haven't already been in contact with them. Then ask if you could discuss cost of living with them. Whenever a prospective student does this with me, I ask if they want numbers and then I am always upfront with my stipend, how much I spend and where I spend it (since different people might have different needs).