Programming the statistical procedures from SAS

Comparision of Slopes

Reply
New Contributor
Posts: 4

Comparision of Slopes


Can someone please provide direction on how to compare two different slopes from two different regression curves for equivalency?  I have data sets with one response and the effect being time.  I have another effect, manufacturer that I want to include to see if there's any difference in the two different regression curves by manufacuturer.  I believe I want to perform an Analysis of Covarience, but can't locate where it is (Using Jmp Ver 8.0.2).  Hope someone can help me.

SAS Employee
Posts: 340

Re: Comparision of Slopes

Just use the Fit Model platform.

Include the 2 effects, and also the interaction. If the interaction (time*manufacturer) is significant, then there is difference in the slope.

New Contributor
Posts: 4

Re: Comparision of Slopes

Gergely,

Thanks for the reply.  So as to be certain, I would add the response (call it activity) as my Y variable and the products age (in months) and the manufacture (a nominal charatcter) as construct model effects?  Or do I have to make the manufactures a numeric/nominal value?

SAS Employee
Posts: 340

Re: Comparision of Slopes

Yes.

If manufacturer is numeric, be careful that its modelling type is nominal.

If manufacturer is character it will be automatically nominal.

New Contributor
Posts: 4

Re: Comparision of Slopes

Gergely,

thanks so much for your help.

Here's what I then get (Hope it's readable).  I don't see the interaction you previously mentioned - (time*manufacturer) given.

Am I doing something incorrectly?

img20150120_10543817.jpg

img20150120_10494726.jpg






SAS Employee
Posts: 340

Re: Comparision of Slopes

Hi,

I don't have JMP right now (and I am using JMP 11), but somewhere in the dialog where you inclue model effects, you can also include the interaction.

In JMP 11 you need to highlight the effects (one effect on the right, one on the left pane), and then click "cross".

New Contributor
Posts: 4

Re: Comparision of Slopes

That's what I thought.  I'll check it out.  Probably time to upgrade.  You've been a big help.

Grand Advisor
Posts: 16,875

Re: Comparision of Slopes

You should post JMP questions to the JMP forum:

https://community.jmp.com/community/discussions

Ask a Question
Discussion stats
  • 7 replies
  • 318 views
  • 6 likes
  • 3 in conversation