I have thousands of rows of data (not sorted).
is there a (easy) way to calculate the average of this data by quartile.
that is average of the bottom 25% of this data, average of next 25% of data
and so on so forth.

Also an added question if we can solve the above is that can i do similar
averages of data on a second column but based on rankings (or quartiles
defined) in the first range?

thanks and looking forward to expert advice as always.

RK