Average Function and dynamic cell address

[spartanmba]

I am sure this is an easy answer for some of you, but I am not sure how to do
this...thanks for your help in advance.

I have an average formula that I would like to dynamically change the number
of rows it averages. For example if I have 25 cells of data, but the user
only wants ten rows for their work. I would have them enter into a cell the
number of points that want averaged and the average formula would dynamically
adjust based upon their entry. I know I need to dynamically create an
address (row and column) information for the forumla, but I am totally lost
on how to do this.

THANKS again!
John

 

[Trevor Shuttleworth]

=AVERAGE(OFFSET(A1,,,B1))

Cells start in A1 and the number of rows to be averaged is in cell B1

Regards

Trevor

 

[Biff]

Here's another one:

A1:A20 = range of values

C1 = number of values to be averaged starting from A1

=AVERAGE(A1:INDEX(A1:A20,C1))

If C1 is empty the formula will calculate the entire range.

If no numbers are in the range you'll get a #DIV/0! error. To prevent that
error:

=IF(COUNT(A1:A20),AVERAGE(A1:INDEX(A1:A20,C1)),"")

Biff