What is the basis for excluding data that is beyond 2.5 Std Dev from the mean.

Why not use the built in quartiles worksheet function against the raw data
to get the quartiles from the raw data. If the data is incorrect, throwing
out the data you suggest doesn't seem to have much justification to me. You
need to get correct data. Nonetheless:

Yes
=Average($m$2:$M$121411)

would give you the average

You could use an adjacent empty column to do

Assume the data points are in M as you show, in R2 for example

=if(Abs(M2-Average($M$2:$M$12411))2.5*Stdev($m$2:$M$121411), "Delete","Keep")

then do an autofilter on column R and select Delete in the dropdown. Select
all the data except the first row and do Edit=Delete and select entirerow.
Note that once you delete the rows (and remove the filter), the formulas will
recalculate and new mean and standard deviation and more rows will show up as
Delete, but you can ignore these.

--
Regards,
Tom Ogilvy


then drag fill down to



"Zone" wrote:

John, I understand. I'll plow away at the problem in here in hopes
that you will stick with me for a while and not get irritated with my
lack of mathematical expertise. I would like to use built-in Excel
functions as much as possible to speed the calculation. Your first
step, "Calculate the mean". Would I use Excel's AVERAGE function for
this? Say column M contains 12,410 numbers, starting on row 2. Would
I then use a formula such as =AVERAGE(m2:m12411) to get the mean? A
friend has told me that what is really wanted is the "threshold to the
second quartile", so I'm confused. James

On Jul 9, 1:48?pm, wrote:
James,

Sorry, that email doesn't exist anymore. The programming is fairly
straight forward. I'll do what I can to help you, but if it isn't
something you are going to do on a regular basis....manual is the way
to go.

John