Formula to average last 25 entries in a column?

[Going Crazy with excel]

Guess I have a duel question.
First, I have numerous columns of data, all numerical. New entries are
entered at the end of the column. Is there a formula to average just the
last 25 entries in the column? (Bottom of column up)
Second question pertains to the ability to "auto populate". I have a column
of names. (three dozen). I would then like to auto populate the single
column of names, matching the names with the average data obtained from the
above. (average of last 25, 50, 100,etc entries) Data changes daily?
Any help would be greatly appreciated.

 

[Mike H]

Hi,

Average last 25 entries

=AVERAGE(OFFSET(A1,COUNTA(A:A)-25,):OFFSET(A1,COUNTA(A:A),))

I don't understand the second question
--
Mike

When competing hypotheses are otherwise equal, adopt the hypothesis that
introduces the fewest assumptions while still sufficiently answering the
question.

 

[Going Crazy with excel]

Sorry Mike, I know what I want, just don't know how to say it.
Maybe an example will help.

Data Sheet one Data Sheet two
Column 1 Column 1 Column 2 Column 3 Column 4
Ralph Sam 199 496 408
Sam Ralph 210 333
535
John Mike 75 322
647
Mike Tim 498 354
657
Tim John 637 577
353

Looking to take the information from Data Sheet two, and auto populate that
data into the matching name on data sheet one. I know I can drag the
information from one to the other, but there are numerous entries for each.
Better?

 

[Steve Dunn]

=AVERAGE(OFFSET($B$1,MAX(COUNT($B:$B)-25,0),,25))

and

=INDEX(Sheet2!$A$1:$E$5,MATCH($A1,Sheet2!$A$1:$A$5,0),COLUMN())

HTH
Steve D.

 

[Steve Dunn]

1st formula should perhaps have been better shown as:

=AVERAGE(OFFSET(B$1,MAX(COUNT(B:B)-25,0),,25))

So it can be copied along to other columns.