topic Re: Comparision of Slopes in Statistical Procedures

Comparision of Slopes

Jdobiecki_charter_net — Mon, 19 Jan 2015 21:40:07 GMT

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.

Re: Comparision of Slopes

gergely_batho — Mon, 19 Jan 2015 22:00:36 GMT

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.

Re: Comparision of Slopes

Reeza — Mon, 19 Jan 2015 22:12:44 GMT

You should post JMP questions to the JMP forum:

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

Re: Comparision of Slopes

Jdobiecki_charter_net — Tue, 20 Jan 2015 14:28:15 GMT

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?

Re: Comparision of Slopes

gergely_batho — Tue, 20 Jan 2015 15:29:18 GMT

Yes.

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

If manufacturer is character it will be automatically nominal.

Re: Comparision of Slopes

Jdobiecki_charter_net — Tue, 20 Jan 2015 15:58:46 GMT

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?

Re: Comparision of Slopes

gergely_batho — Tue, 20 Jan 2015 16:08:07 GMT

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".

Re: Comparision of Slopes

Jdobiecki_charter_net — Tue, 20 Jan 2015 16:39:29 GMT

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