Is there a way to use data ranges as axis points?

e.g given

Age Qty
20 1
23 5
40 7
41 6

Create two points (Age : range 20-30 and then range 40-50) with (Qty:
Average of Qty for 20-30 and then average of Qty for 40-50)

as 20-30 , 3 and 40-50 6.5

and then plot it?

I can do this with a macro but would like to do without the code. Thanks.