Average last 6

K

Kwanjangnim

hi all
i've had a look through all the other threads but haven't bee able to find
the solution i'm looking for, basically i have a column which has a numeric
value entered (in each row) according to results in other cells. see example
below

A
1 l 10
2 l -10
3 l 12
4 l 0
5 l 16
6 l -11
7 l 10
8 l
9 l

i need a funchtion that will average ONLY the last 6 results (a2:a7), this
column will be updated as new results are added, therefore the range that
needs to be averaged will constantly change to so that ONLY the last 6
entries will be averaged.
(a1:a50) will be the max range so cells with no entries (blanK) will need to
be ignored. can anyone help?
 
B

Bob Phillips

=AVERAGE(A200:INDEX(A1:A200,SUMPRODUCT(LARGE(ROW(1:200)*(A1:A200<>""),6))))

--

HTH

RP
(remove nothere from the email address if mailing direct)
 
K

Kwanjangnim

thanks for the code, it worked well when i tested it in a blank worksheet,
however for some reason it doesn't work when placed in my worksheet, i keep
getting a 'divide by zero error' but all i changed from your formula was the
col range and the start row and end row no.s
=AVERAGE(B76:INDEX(B7:B76,SUMPRODUCT(LARGE(ROW(7:76)*(B7:B76<>""),6)))) the
empty cells that are awaiting results from other cells have been formulated
to display blank but i keep getting 'DIV/0' can you sort this for me?
 
R

Ragdyer

I must say that Bob did a good job with this formula!

However, there's just a coincidence between the range in his example and the
actual size of the range itself.

Your range is 70 rows, so revise your formula to this:

=AVERAGE(B76:INDEX(B7:B76,SUMPRODUCT(LARGE(ROW(1:70)*(B7:B76<>""),6))))
 
D

davidm

Just curious. How can Bob's formula be tweaked to handle a generic
situation where* the last 6 rows in Column A* are always averaged.
 
D

davidm

Just curious. How can Bob's formula be tweaked to handle a generic
situation where* the last 6 rows in Column A* are always averaged.


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B

Bob Phillips

Hi David,

=AVERAGE(A65336:INDEX(A1:A65336,SUMPRODUCT(LARGE(ROW(1:65336)*(A1:A65336<>""
),6))))

although you wont want many of these in your spreadsheet <g>

--

HTH

RP
(remove nothere from the email address if mailing direct)
 
K

Kwanjangnim

I still have the 'Div/0' error that needs fixing any suggestion, please read
previous thread for details
 
R

RagDyer

If you revised your formula as I suggested, and you're still getting that
#DIV/0! error, then I would guess that your numbers are *not numbers*.

Now, your OP said that these numbers were the *results* from other cells.

Are there formulas in B7:B76?

If so, post back with the formulas.

Also, you could try this formula to test the contents of Column B:

=ISNUMBER(B7)&"-"&LEN(B7)

Copy down and make sure that you see "True", and that the number returned
matches the visible characters in the formula bar ( i.e formats - $ - don't
count)
 
K

Kwanjangnim

yeah there are formulas in b7:b76
"=IF(ISNA(N18+(SUM(I18:M18))),"",N18+(SUM(I18:M18)))"

=AVERAGE(B76:INDEX(B7:B76,SUMPRODUCT(LARGE(ROW(1:70)*(B7:B76<>""),6)))) is
what you revised, but i just wanted to check that "(ROW(1:70)" not ment to be
"(ROW(7:76)" it doesn't matter anyway coz i still get "div/0" error

will use the "=ISNUMBER(B7)&"-"&LEN(B7)" to validate col b and get back to you

thanks for your help so far
 
K

Kwanjangnim

update: not that it matter for the examples i'm testing but in my worksheet
b7:b76 is actually r7:r76

and the validation formula returned "false-0" "=ISNUMBER(r18)&"-"&LEN(r18)"

cheers
colin
 
R

RagDyeR

You got a return of "False-0" for R18?!?!?!

When you just said that those cells contained the formula:
"=IF(ISNA(N18+(SUM(I18:M18))),"",N18+(SUM(I18:M18)))"

Does that means that you have a #N/A error in the I18:N18 range, and R18
looks empty?

Also, is the entire R6:R76 range populated with the IF() formula?

Perhaps you might wish to send me a copy of your sheet.

Cut out cutout from my address.


Regards,

RD
----------------------------------------------------------------------------
-------------------
Please keep all correspondence within the Group, so all may benefit !
----------------------------------------------------------------------------
-------------------

update: not that it matter for the examples i'm testing but in my worksheet
b7:b76 is actually r7:r76

and the validation formula returned "false-0" "=ISNUMBER(r18)&"-"&LEN(r18)"

cheers
colin
 
R

RagDyeR

The sheet is on the way back to you.

I didn't change anything in your sheet *except* what was in Column R.
In fact, I didn't even change R, but added revised formulas to Column S,
right along side.

I didn't get into the intricacies of your sheet and formulas, so make sure
that the change I made won't screw anything else up that I might not have
noticed.

It seems that the error message generated by your Sum formula caused all the
problem.

I *didn't* see that #DIV/0 error that you kept mentioning about in your
posts.

--

Regards,

RD
----------------------------------------------------------------------------
-------------------
Please keep all correspondence within the Group, so all may benefit !
----------------------------------------------------------------------------
-------------------


You got a return of "False-0" for R18?!?!?!

When you just said that those cells contained the formula:
"=IF(ISNA(N18+(SUM(I18:M18))),"",N18+(SUM(I18:M18)))"

Does that means that you have a #N/A error in the I18:N18 range, and R18
looks empty?

Also, is the entire R6:R76 range populated with the IF() formula?

Perhaps you might wish to send me a copy of your sheet.

Cut out cutout from my address.


Regards,

RD
----------------------------------------------------------------------------
-------------------
Please keep all correspondence within the Group, so all may benefit !
----------------------------------------------------------------------------
-------------------

update: not that it matter for the examples i'm testing but in my worksheet
b7:b76 is actually r7:r76

and the validation formula returned "false-0" "=ISNUMBER(r18)&"-"&LEN(r18)"

cheers
colin
 
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