topic Standard Deviation Help in App Development

Standard Deviation Help

Coombsie — Mon, 28 Jun 2021 16:55:18 GMT

I'm struggling to get a standard deviation result to match excel which it must as the results must match previously issued figures.

I have simplified the data down to just a list of results so I can use a straightforward expressions of just stdev(Result).

I have also tried adding a multiplier '*sqrt((n-1)/n)' which only made a fractionally small change to the result.

I have attached some sample data which excel gives a result of 26.6% however Qlik Sense gives a result of 13.7%.

Is anyone please able to tell me how to calculate this so the figures match?

Re: Standard Deviation Help

Coombsie — Wed, 21 Jul 2021 10:06:33 GMT

Hi. This post has been up for a few weeks. Is anyone able to help with this one as I am at a loss still on how the get the figures to match? Any assistance will be greatly appreciated

Re: Standard Deviation Help

chrismarlow — Wed, 21 Jul 2021 11:04:28 GMT

Hi,

Have you tried putting the data from your spreadsheet into a separate app?

If I do I get the Excel result (see below), suggests to me that the StDev is not being calculated on what you think it is being calculated on. I did try excluding the 0's to see if I could get the 13.7, but don't get the same value.

Where I would go next with this is I think you need an AGGR to pre-aggregate before applying the StDev, but you would need to share more on how the data you have shared came together to say more than that.

Cheers,

Chris.