Random sample

[Ariel.Prizont]

I need to take a random sample of 400 rows out of 16,000.
What would be the best function in excel to use?

 

[Frank Kabel]

Hi
one way:
- in a helper column adjacent to your data put the formula
=RAND()
and copy down for all rows

After this sort with this column and use the first 400 entries as your
sample

 

[Tushar Mehta]

For a few different options see
Random Selection
http://www.tushar-mehta.com/excel/newsgroups/rand_selection/index.html

--
Regards,

Tushar Mehta
www.tushar-mehta.com
Excel, PowerPoint, and VBA add-ins, tutorials
Custom MS Office productivity solutions

 

[Richard Dobis]

Let me repeat your problem to see whether I understand.

You have 16000 row (and each of them contains numbers text etc )
You want to randomly choose 400 rows out of given 16000.

If I am right then you should use function OFFSET and RAND together.

Let in column A (A1:A16000) are 16000 numbers
Let in column B (B1:B400) are formulas =FLOOR(RAND()*16000,1)
And let the column C (C1:C400) is filled by formulas =OFFSET($A$1,B1,0) (B1
for row 1 -> B2 for row 2 -> B3 for row 3 etc)

After each F9 column C is different random sample (uniformly distributed)
from A.
I think that this number example could be easily transformed into your
problem with rows.

rd

PS: later on you can change B column to =FLOOR(RAND()*(16000-1)+1,1), which
is more appropriate formula for you.