%RSD

[Kwei]

Help me find the %RSD formulae in the Excel spreadsheet

[Bernard Liengme]

And this is what?
best wishes

--
Bernard V Liengme
Microsoft Excel MVP
http://people.stfx.ca/bliengme
remove caps from email

"Kwei" <Kw...@discussions.microsoft.com> wrote in message
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[Fred Smith]

What's RSD?

Regards,
Fred

"Kwei" <Kw...@discussions.microsoft.com> wrote in message
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[Glenn]

Kwei wrote:
> Help me find the %RSD formulae in the Excel spreadsheet

=STDEV(A1:A10)*100/AVERAGE(A1:A10)

[Glenn]

Bernard Liengme wrote:
> And this is what?
> best wishes
>

Relative Standard Deviation

[JoeU2004]

That is the way I always see the RSD formula written. But I wonder: is
the purpose of scaling by 100 simply to make the percentage appear as a
number between 0 and 100, but it is still interpreted as a percentage; or is
the statistic always expected to be scaled by 100, and it is interpreted as
an index?

Put another way, if the std dev is 4 and the mean is 8, would I say "the RSD
is 50", or would I say "the RSD is 50 percent".

If the latter, I would write the Excel formula as one of the following,
depending on whether the population or sample std dev is appropriate for the
statistical situation:

=STDEVP(A1:A10) / AVERAGE(A1:A10)

=STDEV(A1:A10) / AVERAGE(A1:A10)

formatted as Percentage (Format > Cells > Number).

[Jerry W. Lewis]

It is a percentage, so you are correct that the % format instead of
multiplying by 100 would be better. %RSD is the more common term in
analytical literature, CV (coefficient of variation) is more common in the
statistical literature.

Jerry