I need help. (Obviously)

How can I find simple (and weighted) averages of a column of numbers...
but not the entire column. Example, I have a column of 50 data points
and want to average the last 8 numbers only. The trick here is that my
data set is 50 columns wide as well, but each successive column gets
one number less. So Column A has 50, from row 1 to 50, Column b has row
1 to 49 etc. all the way to one row only out at column 50. I want to
average the last 8 numbers only and then drag my formula across all
columns and not have to go into the formula bar and change my array by
one row for each column.

Does this make sense? If anyone is an actuary I am working on insurance
loss development triangles if that helps. I am trying to make getting my
LDF picks easier.

Thanks,

Jason


--
Bootroots
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Bootroots Wrote:
> I need help. (Obviously)
>
> How can I find simple (and weighted) averages of a column of numbers...
> but not the entire column. Example, I have a column of 50 data points
> and want to average the last 8 numbers only. The trick here is that my
> data set is 50 columns wide as well, but each successive column gets
> one number less. So Column A has 50, from row 1 to 50, Column b has row
> 1 to 49 etc. all the way to one row only out at column 50. I want to
> average the last 8 numbers only and then drag my formula across all
> columns and not have to go into the formula bar and change my array by
> one row for each column.
>
> Does this make sense? If anyone is an actuary I am working on insurance
> loss development triangles if that helps. I am trying to make getting my
> LDF picks easier.
>
> Thanks,
>
> Jason

Try this and see if it helps you.

*=average(offset($A$1,count(A1:A50)-8,0,8))*


--
BenjieLop


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Bootroots Wrote:
> I need help. (Obviously)
>
> How can I find simple (and weighted) averages of a column of numbers...
> but not the entire column. Example, I have a column of 50 data points
> and want to average the last 8 numbers only. The trick here is that my
> data set is 50 columns wide as well, but each successive column gets
> one number less. So Column A has 50, from row 1 to 50, Column b has row
> 1 to 49 etc. all the way to one row only out at column 50. I want to
> average the last 8 numbers only and then drag my formula across all
> columns and not have to go into the formula bar and change my array by
> one row for each column.
>
> Does this make sense? If anyone is an actuary I am working on insurance
> loss development triangles if that helps. I am trying to make getting my
> LDF picks easier.
>
> Thanks,
>
> Jason

Try this and see if it helps you.

*=average(offset($A$1,count(A1:A50)-8,0,8))*


--
BenjieLop


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Hi

One way, place the following formula in say cell A52
=SUM(INDEX(A1:A50,COUNT(A1:A50)-MIN((COUNT(A1:A50)-1),7)):INDEX(A1:A50,COUNTA(A1:A50)))/8

Copy across for all of your columns


--
Regards

Roger Govier


"Bootroots" <(E-Mail Removed)>
wrote in message
news:(E-Mail Removed)...
>
> I need help. (Obviously)
>
> How can I find simple (and weighted) averages of a column of
> numbers...
> but not the entire column. Example, I have a column of 50 data points
> and want to average the last 8 numbers only. The trick here is that my
> data set is 50 columns wide as well, but each successive column gets
> one number less. So Column A has 50, from row 1 to 50, Column b has
> row
> 1 to 49 etc. all the way to one row only out at column 50. I want to
> average the last 8 numbers only and then drag my formula across all
> columns and not have to go into the formula bar and change my array by
> one row for each column.
>
> Does this make sense? If anyone is an actuary I am working on
> insurance
> loss development triangles if that helps. I am trying to make getting
> my
> LDF picks easier.
>
> Thanks,
>
> Jason
>
>
> --
> Bootroots
> ------------------------------------------------------------------------
> Bootroots's Profile:
> http://www.excelforum.com/member.php...o&userid=36126
> View this thread:
> http://www.excelforum.com/showthread...hreadid=558989
>

=AVERAGE(LARGE(IF(A1:A50<>"",ROW(A1:A50)),ROW(INDIRECT("1:"&MIN(8,COUNT(A1:A
50))))))

which is an array formula, it should be committed with Ctrl-Shift-Enter, not
just Enter.

Copy across


--
HTH

Bob Phillips

(replace somewhere in email address with gmail if mailing direct)

"Bootroots" <(E-Mail Removed)> wrote
in message news:(E-Mail Removed)...
>
> I need help. (Obviously)
>
> How can I find simple (and weighted) averages of a column of numbers...
> but not the entire column. Example, I have a column of 50 data points
> and want to average the last 8 numbers only. The trick here is that my
> data set is 50 columns wide as well, but each successive column gets
> one number less. So Column A has 50, from row 1 to 50, Column b has row
> 1 to 49 etc. all the way to one row only out at column 50. I want to
> average the last 8 numbers only and then drag my formula across all
> columns and not have to go into the formula bar and change my array by
> one row for each column.
>
> Does this make sense? If anyone is an actuary I am working on insurance
> loss development triangles if that helps. I am trying to make getting my
> LDF picks easier.
>
> Thanks,
>
> Jason
>
>
> --
> Bootroots
> ------------------------------------------------------------------------
> Bootroots's Profile:
http://www.excelforum.com/member.php...o&userid=36126
> View this thread: http://www.excelforum.com/showthread...hreadid=558989
>

Thanks everyone! I will try all and see what works for me.


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Bootroots
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