topic Re: Standard deviation in QlikView

Standard deviation

Thu, 05 Nov 2015 11:55:43 GMT

Hello,

I have a only one table with one row:

LOAD * INLINE [

ITEMID, INVENTLOCATION, DATE, sales

026381, Ł1, 2013-Mar, 1

];

I want to create table with calculation of standard deviation:

dimension: ITEMID,INVENTLOCATION

expression: =stdev(aggr(sum(sales),INVENTLOCATION, DATE))

Why field of this expression is empty?

Re: Standard deviation

Clever_Anjos — Thu, 05 Nov 2015 12:19:08 GMT

Standard Deviation calculation needs at least two values

If you have only one value, you´ll have 0/0 that is undefined

Re: Standard deviation

Thu, 05 Nov 2015 12:23:16 GMT

the same result with this script:

LOAD * INLINE [

ITEMID, INVENTLOCATION, DATE, sales

026381, Ł1, 2013-Mar, 1

];

Re: Standard deviation

Clever_Anjos — Thu, 05 Nov 2015 12:41:10 GMT

Again, you´re having only one value, since your INVENTLOCATION, DATE are the same, so your AGGR() will return only one value.

LOAD * INLINE [

ITEMID, INVENTLOCATION, DATE, sales

026381, Ł1, 2013-Mar, 1

026381, Ł1, 2013-Abr, 1

];

will return "0", because your AGGR() will return 2 similars values

Re: Standard deviation

Tue, 17 Nov 2015 14:31:36 GMT

Ok, I have problem with this. Why when I don't selected ITEMID expression =stdev(aggr(sum(sales),INVENTLOCATION, DATE)) is not calculated for all ITEMID. When I select only one ITEMID this expression is calculated?

Re: Standard deviation

Clever_Anjos — Tue, 17 Nov 2015 16:35:23 GMT

Could you post a sample of your app?

Re: Standard deviation

Wed, 18 Nov 2015 07:21:24 GMT

In attachment

Re: Standard deviation

Clever_Anjos — Thu, 19 Nov 2015 16:28:21 GMT

If you use an AGGR inside an object that has dimensions usually those dimensions must be into your aggr expression.

Please check if this formula returns what you need

=stdev(aggr(sum(ilosczfak),ITEMID,INVENTLOCATIONIDLOG2, INVOICEMONTH))

Re: Standard deviation

Clever_Anjos — Thu, 19 Nov 2015 16:29:48 GMT

Please check #4 into Pitfalls of the Aggr function