## Find standard deviation in Excel, but first develop a labor-saving trick

Help me with statistics and Excel. Especially help me if you know any labor saving methods. I want the median, mean and standard deviation for the average price of all items sold, but my spreadsheet-full-of-data doesn't tell me the price of each sale -- just the average price per store, and the number sold at that store. Something like this:
posted by croutonsupafreak on Jun 21, 2013 - 10 answers

## How to Find The Average Commenter?

Harmonic or Arithmetic Mean?: I'm trying to settle an argument with my wife - is using the arithmetic mean or harmonic mean more appropriate when finding the "average" number of, say, online comments made by a large number of people, where a significant portion of them make only one comment and a few people make the bulk of the comments?
posted by salsamander on Jun 2, 2012 - 13 answers

## Help me sample accurately!

Please provide me with an *effective*, and statistically sound, table/chart listing suggested sample size guidance for associated population size
posted by thankyoumuchly on Jan 14, 2010 - 11 answers

## I know there's some sort of Law of Why This Shit Works

MathFilter: When you take the average of a series of ratios expressed as fractions, you get the same result whether you add together all of the fractions, then divide them by the size of the series or divide the sum of all of the numerators by the sum or all of the denominators. What's this called, and what's the formal proof for this look like?
posted by ignignokt on Oct 29, 2008 - 14 answers

## There's a good reason I went into music instead of engineering

Grading dilemma: Can the median be a fair measure of a set of quiz scores? Here's the situation ...
posted by imposster on May 8, 2006 - 24 answers

## Help me understand weighted averages.

Remedial weighted averages for the mathematically illiterate – or, can the 10% of you who understand math help the remaining 95% of us who don't? [mi].
posted by RavinDave on Jul 11, 2004 - 3 answers

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