"Average" questions

[Bootroots]

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

[BenjieLop]

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]

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))

[Roger Govier]

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" <[email protected]>
wrote in message
news:[email protected]...
>
> 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
>

[Bob Phillips]

=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" <[email protected]> wrote
in message news:[email protected]...
>
> 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
>

[Bootroots]

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