Does this help:
1. Create a general module in the VBA editor: Insert > Module
2. Copy/paste into the module all the functions from item 4 of the link I provided. Here it is again
http://support.microsoft.com/kb/209839
3. In query or in textbox on form or report use the expression I show in earlier post. Here it is again:
RAvg([1A], [1B], [1C], [1D], [1E], [1F], [1G], [1H], [1I], [1J], [2A], [2B], [2C], [2D], [3A], [3B], [3C], [3D], [3E], [3F], [3G], [4A], [5A], [5B], [5C], [5D], [5E], [5F], [5G], [5H], [6A], [6B], [6C], [7A], [7B], [7C], [7D], [7E], [7F], [7G], [7H], [7I], [7J])