Another possible way using a helper column, the MOD() function and Auto Filter:

Put a formula in a cell on the same row with the first reading such as
=MOD(ROW(),5)
and fill that down to the end of your data readings and then use Data |
Filter | Auto Filter to choose the value that will give you the number of
readings per second that you want. Copy what is displayed to another sheet.

Try various values for the '5' in the formula above to get the granularity
you want, some factor of 60 such as 2, 4, 5, 6, 10, 12, 15 (or a multiple of
one of those) should get you the sampling you want.


"Rob" wrote:

I have large files that are to be analysed, which are taken from a
recorder at 60 Hz. Sixty readings per second is far more than
necessary for my purposes, and I wondered whether there is a quick way
to 'refine' this data, like make a new file from the existing one that
has 5 or six readings per second.... What's the quickest way to do
this?

Any help would be appreciated!

Rob