my data look like this(see pic) What type of regression should be used ?

Thanks for any idea. Vladimir.

enter image description here

  • $\begingroup$ Do you want the lines to meet at k as you have drawn it or do you just want different slopes? $\endgroup$ – mdewey Jan 9 '17 at 12:13
  • $\begingroup$ Lines meet in k $\endgroup$ – kenar Jan 9 '17 at 12:19

I would suggest a linear model with an interaction between Age and a categorical variable created using the dummy variable Age>K. That way the gradient of the slope can be varied by whether your dummy variable is 1 or 0 (i.e. Age >K or <=K)

$Y$ = $\alpha$+$\beta_{1}$Age + $\beta_{2}$Age:Dv + $\epsilon$

Where Dv is your dummy variable.

The gradient of the slope between Y and Age when Dv=1 will be $\beta_{1}$ + $\beta_{2}$ and just $\beta_{1}$ when Dv=0. Thus, you'll end up with a change in gradient at K.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.