Variance / écart type

[jsdondon]

Hi,

I've got an error with variance in qlikview

This is the series of grades obtained in the by 70 students

COUNTRY	NB_STU	NOTES
P1	1	4
P1	1	5
P1	7	6
P1	3	7
P1	10	8
P1	12	9
P1	8	10
P1	2	11
P1	6	12
P1	6	13
P1	6	14
P1	3	15
P1	2	16
P1	0	17
P1	1	18
P2	1	20
P2	1	10

I need to calculate variance for each country such as

	VARIANCE
P1	9,370891
P2	25
P1+ P2	10,46714

I’ve used formula

sum(

            (

            NB_STU

            )

            *

            sqr(

                        NOTES -

                                    sum(

                                               total

                                               Aggr(Sum(NOTES * NB_STU), COUNTRY)

/Aggr(Sum(NB_STU), COUNTRY)

                                               )

                        )

            )

/

sum(Aggr(Sum(NB_STU), COUNTRY))

It works only if I filter data on a country

PAYS	VARIANCE
PAYS1	9,37

But KO when no filter

PAYS	VARIANCE
PAYS1	234,37
PAYS2	128,26

I can’t identify what is wrong, could someone help please?

Thanks a lot

[ogautier62]

hello,

use function stdev() for standard deviation it's more simple,

regards

[jsdondon]

Hi,

Thanks for the function but I can't see how to use it with two kpi

[ogautier62]

Remove word total in sum (total aggr(

[ogautier62]

Hi

I apologize you're rigth for your formula, stdev doesn't work

regards