R2 value for a plot

[#1]

I have 2 variables in my dataset and want to know how well a regression without intercept fits the data.

I predict Y by using X

so my regression formula is Y= B*X

Using Linear regression.

The measurement for the goodness of the fit is the R2.

the formula for R2=

1-(RRerr/RRtot)

see: http://en.wikipedia.org/wiki/Coefficient_of_determination

I understand the concept of regression and the formula of R2, but I can's seem to get this working in qlikview.

Anyone know how?

see trial dataset in attachment

[swuehl · Accepted solution]

You may want to take a look into the linest_XXXX function sets (search the Help for statistical aggregation functions in charts).

So maybe

=LINEST_R2(y,x)

is what you are looking for?

[#3]

Your answer works thanks!

I was trying to type the whole formula for R2 myself... too tricky to make mistakes...

The only problem I still have is the following:

I want a regression without a constant.

So I figured you should type linest_r2(y,x,0).

However, this doesn't work. Neither does linest_r2(y,x,'0').

linest_r2(y,x) works though. But I guess this is the R2 of a regression of y=mx + b and not y=mx

[swuehl]

In this case, I think linest_r2(y,x,0) should be used. This is also what the help says.

Specifying the y0 does work with other linest functions, if it does not work with linest_r2, I have no clue yet.

[#5]

no it does not work for linest_r2 (anyway, not in my file).

the trial dataset is attached with my first post...

[swuehl]

I'll be offline for a few days.

If feasible, you may want to contact support, I think this could be a bug, it's not working as described (in the Help).

I could maybe Help you in rebuilding (like you initially tried) the expression, but not before mid of next Week.

[jansen28]

Hi Kenneth, I'm working on the linest_r2 calculation. I'm using the below formula to calculate r2.

where,

vmindate = 12/30/2013

vgetfield = 06/01/2014

=LINEST_R2({<Date = {'>=$(vmindate) <=$(=vgetfield)'}>}x,y)

I get null value. Does Linest_r2 works in qlikview or Am I using incorrect calculations.

I appreciate your help Kenneth....

Regards,

Jan

[Anonymous]

Hi Janani,

Were you able to get value using  LINEST_R2() with date condition.