Multiple averages in large continous data field

[Me]

In column C I have the date, in column D I have the time, and in column E I
have a measurement taken at that date/time period. There’s 25,000+ rows of
this data, so doing what I need wouldn’t be something easily done manually.

Based on the date and time, I would like to find the average of the
measurements taken per date, per shift. Dayshift is 7:00 AM until 9:00, and
nightshift is 9:01 PM until 6:59 AM.

I would like to post the results for each shift per date in column G at the
first two rows per date. There are about 200 rows per date, so where the
results would be about 200 rows apart.

Is there anyway this can be done?

Thanks in advance.

 

[Bob Phillips]

Does the date of the night shift cover two days, for example

20/08 for 9:00PM to midnight

and

21.08 for midnight to 6:59AM.

is that the same day?

--
HTH

Bob

(there's no email, no snail mail, but somewhere should be gmail in my addy)

 

[Me]

No, that would not be the same day. Thanks for double checking - I should
have mentioned that.

BTW, I am using Excel 2003 if that matters.

Thank you.