topic Liner regression in QlikView

Liner regression

Wed, 25 Nov 2020 16:16:04 GMT

Hello,

I found liner regression model y=a+bx. I separately found coefficients a and b by using this formulas:

b = (sum(Sales*GP)-(1/Count(GP))*(sum(Sales)*sum(GP)))/(Sum(pow(Sales,2))-(1/Count(GP))*pow(sum(Sales),2))

a = avg(GP)-$(b)*avg(Sales)

b = 0.21566

a = - 0.99533

When expression is - 0.99533+0.21566*Sales everything OK.

When i trying visualize my liner regression using this expression $(a)+$(b)*Sales it shows me only one point not a line. Why?

sunny_talwar — Wed, 12 Oct 2016 15:56:27 GMT

Have you tried the values in text box? If you did, did you try a or $(a)? May be you do not need to use dollar sign expansion here

a + (b*Sales)

Anil_Babu_Samineni — Wed, 12 Oct 2016 16:00:52 GMT

Try this

('$(a)')+('$(b)'*Sales)

julian_rodriguez — Wed, 12 Oct 2016 16:34:26 GMT

Try adding the equal symbol "=" before the expression on the variable definition, like this:

b = = (sum(Sales*GP)-(1/Count(GP))*(sum(Sales)*sum(GP)))/(Sum(pow(Sales,2))-(1/Count(GP))*pow(sum(Sales),2))

a = = avg(GP)-$(b)*avg(Sales)

MarcoWedel — Wed, 12 Oct 2016 19:35:44 GMT

Hi,

maybe you could use predefined functions instead:

hope this helps

regards

Marco