topic How does Stdev works in qlik view? in QlikView

How does Stdev works in qlik view?

Thu, 28 Feb 2013 10:20:20 GMT

I tried drilling down on the function stdev and I found out that it is equal to stdev.s of excel.
Excel has 2 ways of calculating standard deviation 1)Stdev.P 2)Stdev.S.

I would like to show how these works. Let us suppose we have 2 nos. 85 and 90.

so if i use Stdev.P ans is 2.5 and that has to be the ans

if i use Stdev.S ans is 3.34.

and the same ans 3.34 is given by qlik view Stdev formula. Isnt it wrong? please guide me

Re: How does Stdev works in qlik view?

swuehl — Thu, 28 Feb 2013 13:30:35 GMT

For large sample sizes, both Excel functions converge. Neither is wrong, it depends on how you derive the mean value (estimate or not). For more details, you should talk to a statistician of your choice.

You can transform Stdev.S into Stdev.P by calculating something like

Stdev.S * sqrt(N-1) / sqrt(N) = Stdev.P

N being your sample size (count of values).

Re: How does Stdev works in qlik view?

Thu, 28 Feb 2013 13:42:00 GMT

Thanks for enlightening me with the conversion forumla..so simple yet requires common sense which i lack a bit...

I was trying from the whole day to write the big whole formula of Stdev.P(taking avg then summing it up then sqrt and all) in qlik view.