## zaterdag, januari 19, 2013

As usual, first the function:

This is quite a different animal. The application of it isn't really sales, on wikipedia it even says that this applies to electricity, but I don't have those kind of figures -- it'll work just as good with my numbers. It no longer takes into account the number of items sold, so our starting table is going to look a bit different:

From the looks of it, we first need a count of the number of entries and divide 1 by that number. In our case, this gives us the following formula:

=1/count([Lines])

In our case, this is 1/12 or : 0.08.

Next, we have to take the second power of each unit price.. easy peasy.

=power([Sold at (unit price)];2)
And next, we need to add those up:

=Sum(Power([Sold at (unit price)];2))

Next, we have to multiply those and take the square-root.

=sqrt(Sum(Power([Sold at (unit price)];2))*(1/Count([Lines])))

The Quadratic mean of the unit price is 167 -- so far, that's the highest mean we got.

More averages coming up.

Peter