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Weighted Average +/- 1 standard deviation

Hi All-

So, I want to take my line chart and add a +/- 1 standard deviation range around my weighted average, but have no idea how to express standard deviations. The line chart is a successful transaction average displayed by date for a client (so 2 dimensions, date and client), and my expression for the rate is basically this:

(sum(success) + sum(recovery)) / (sum(total transactions)

I basically want 2 reference lines around my rate: +1 stnd dev and -1 stnd dev. I'd really love to put some fancy green shading in between these lines, but that's a want versus a need... Any ideas folks? Thank you!

3 Replies
Gysbert_Wassenaar

Perhaps the example you can find here helps: QlikView Control (SPC) Chart


talk is cheap, supply exceeds demand
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Author

I'm working in Sense, so the expressions mentioned might be similar but the interface sure isn't with that document. Also, my average isn't already aggregated as it is in that example; I'm using Qlik to calculate averages with the expression I listed above.

Gysbert_Wassenaar

The expressions will be the same for both Qlik Sense and Qlikview. And in both cases you'll want to use a line chart with one dimension and multiple expressions. So it should work just the same for Qlik Sense. Only the UI to add the expressions/measures differs.

And the average in the example isn't already aggregated. The expression for the Average Proces Time is Avg (ProcessTime). The expression to calculate the standard deviation is Stdev(total aggr(avg(ProcessTime),Hour)).

In your situation I expect you need something like this:

Stdev(total aggr((sum(success) + sum(recovery)) / (sum(total transactions), YourChartDimensionHere ))


talk is cheap, supply exceeds demand