topic Re: Formula for Cumulative Weighted Mean in Discussions

Formula for Cumulative Weighted Mean

saitcopuroglu — Wed, 19 Oct 2016 02:02:39 GMT

Dear All,

If I have a simple formula as;

ADB=Sum(NetRevenue) / Sum(AdultNight) which is €70.48 = €7,646,735.88 / 108,498 in this data set.

How will I calculate the Cumulative Weighted Mean of ADB (weight=AdultNight) by Sales Date to visualise "ADB Cumulative Mean vs. Sales Date"

The formula I know can not calculate the weight which puts out the wrong final ADB as €68,51

Tables attached

Many thanks in advance for your help.

Re: Formula for Cumulative Weighted Mean

ms — Sat, 27 Feb 2016 15:25:24 GMT

Does this formula return the numbers you want?

Sum(:Name("Sum(NetRevenue)")[1 :: Row()]) / Sum(:Name("Sum(AdultNight)")[1 :: Row()])

Re: Formula for Cumulative Weighted Mean

saitcopuroglu — Sun, 28 Feb 2016 15:15:09 GMT

Yes it does! Thank you.

Is formula

Sum(:Name("Sum(NetRevenue)")[1 :: Row()])

a way of calculating the Cumulative Sum?

If I would change the Sum with Mean would it calculate the Cumulative Mean?

Re: Formula for Cumulative Weighted Mean

ms — Sun, 28 Feb 2016 19:11:10 GMT

Yes.

Mean(:ADB[1::Row()])

should give the same result as your formula

If(Row() == 1,

:ADB,

(:ADB Cumulative Mean[Row() - 1] * (Row() - 1) + :ADB) / Row()

)

However, for very large tables your formula would probably be significantly faster, despite the conditional structure, because it does not require extracting a matrix for each row.