Try the following...

1) Select B11

2) Define the following ranges:

Insert Define Name

Name: Date

Refers to:
=Sheet1!$A$14:INDEX(Sheet1!$A$14:$A$65536,MATCH(9. 99999999999999E+307,She
et1!$A$14:$A$65536))

Click Add

Name: Readings

Refers to:
=Sheet1!B14:INDEX(Sheet1!B14:B65536,MATCH(9.999999 99999999E+307,Sheet1!$A
$14:$A$65536))

Click Ok

3) Enter the following formula in B11 and copy across:

=AVERAGE(IF((DateTODAY()-30)*(Readings0),Readings))

....confirmed with CONTROL+SHIFT+ENTER, not just ENTER.

4) Use conditional formatting to hide #DIV/0! error values that will
result when there's no data. If you need help with this, post back.

Hope this helps!

In article ,
"Sick Puppy" wrote:

First, Harkawat, thanks to both you and Domenic for replying -- especially so
quickly!

Next, I hope you and Domenic will both forgive me. I should have been more
descriptive and specific in my initial post.

I actually have it so that I can enter information for each of these time
periods:

Date | Morning | Noon | Afternoon | Evening | Night

To help me explain easier, please open this screen-shot image of my
spreadsheet:
http://home.earthlink.net/~wiff.them/Image1.jpg

As you can see (hopefully), "Date" is a single, date formatted column.

The other, time-of-day items are actually headings which are centered across
4 columns. The 4 columns are not labeled, but a

Systolic (higher BP reading) | / | Diastolic (lower BP reading) | Pulse

On any given day, I may only take Blood Pressure readings in one, two,
three, etc., of the daily time periods. I also might skip taking readings
for a day -- or skip taking readings for several days.

Because of these situations, I would end up with occasional blank cells in
the range to be averaged, and it also might be that I would not have entries
for 30 consecutive days. I suppose it could be that I might only have 5 rows
of entries that extend back 30 days and should be averaged.

The key is that I want to be able t average all the readings I took during
the previous 30 days, but no further back.

I hope I am being clearer now.

THANKS AGAIN for your assistance!!!

Tim

From: The Mountain, Cough Drop Div.
···· Date & Time Composed ····
June 22, 2005
2:54 pm EASTERN STANDARD TIME -- USA