Select data within a range

I have to work with multiple data sets everyday and I need to follow the same procedure for each data set.
So this is not a 'one time' thing. I am fine with basic excel and that's where my experience is limited to.

I need to select data based on a range that I define.

Column A to B are values I define
Column E to H is the data range
Column J to M are the results I need. (just the average values within that range actually)

A formula that takes the range i define, looks through the data range and gives the average within that range would make my life a whole lot easier.

If anyone could help me please.