Liner regression

[#1]

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]

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]

Try this

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

[julian_rodriguez · Accepted solution]

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]

Hi,

maybe you could use predefined functions instead:

LINEST_M - chart function ‒ QlikView

LINEST_B - chart function ‒ QlikView

hope this helps

regards

Marco