I am using Exel to analyze mechanical test date. The data files can be
600 to 6000 points. I need to capture an 50 point average at the 25%
and 75% points in the data. Is there a way to auto adjust where the
averages are taken based upon the number of data points. I can get the
number of data points using the COUNTIF function. Is there a way to
add this result as the numeric part of a cell reference and do the
appropriate math to select the correct ranges. I hope this explanation
makes sense.

Don't multipost. Either post in *ONE* newsgroup only or *CROSSPOST* to
several newsgroups at the same time. Multiposting, which means posting the
same message to several newsgroups separately, wastes everyone's time.