comparison of slopes

[#1]

After running an ANCOVA model with more than two values of the categorical variable, how can I perform pairwise comparisons of slopes?

Hillary.

[#2]

Thank you, Karen and Julian, On the Fit Model platform the parameter

estimates table also gives a t-test for each slope as compared to the

average slope. Or one can use the indicator function parametrization and

get a comparison of each slope to that of the last category. But other

specific pairs can only be compared by changing the order of the categories

and rerunning the model: very tedious if you have, say, 10 categories.

From: julian

Sent: Thursday, May 26, 2016 7:27 PM

To: Hillary Voet <hillary.voet@mail.huji.ac.il>

Subject: Re: - comparison of slopes

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comparison of slopes

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[#3]

Hi Hillary,

I hope you saw my previous post with the add-in to take some of the tediousness out of rerunning the report. Here's that link again if not:

Compare Simple Slopes in One-Way ANCOVA (w Interaction) add-in​

Julian

[#4]

Thanks, Julian. I'm not familiar with using add-ins.

Hillary.

From: julian

Sent: Thursday, May 26, 2016 9:12 PM

To: Hillary Voet <hillary.voet@mail.huji.ac.il>

Subject: Re: - comparison of slopes

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[#5]

Add-ins extend the functionality of JMP using the built-in scripting language, JSL. Download the add-in from the page, and when you open it JMP will ask you if you wish to install the add-in. Click yes, and you will see a new menu appear called Add-ins. From that menu you can now select the add-in I wrote.

You'll find many other useful add-ins in the file-exchange section of the user community.  It's worth a look around!

Julian

[#6]

Yes indeed! Thanks for the tip about add ins. However: I installed the Add

In as you instructed and ran the Fit Model. When I click on Add Ins and the

name of your add in I get a message "Select a Fit Model Least Squares

Report". How do I do this?

Hillary.

From: julian

Sent: Thursday, May 26, 2016 9:47 PM

To: Hillary Voet <hillary.voet@mail.huji.ac.il>

Subject: Re: - comparison of slopes

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comparison of slopes

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[#7]

HI Julian,

I see you've uploaded the second version of the Add In and it's working

better. However this is the table I get:

which is different from your description of the Add In" the reference

category isn't listed (should be Status 4) and the table doesn't continue

for other reference categories.

Thanks,

Hillary.

From: julian

Sent: Thursday, May 26, 2016 9:47 PM

To: Hillary Voet <hillary.voet@mail.huji.ac.il>

Subject: Re: - comparison of slopes

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comparison of slopes

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[#8]

Hmm, looks like the script is failing somewhere if that's the output you get. I suspect it might have to do with having numbers as the levels of your categorical factor of Status. When the script looks to make a list of those to shuffle the value ordering it appears to take them in as a matrix not a list. I'll find a workaround for this and post a new version.

[#9]

Hi Hillary,

I believe I fixed the issue. Download v0.03 and reinstall and please let me know if you get the expected output.

Compare Simple Slopes in One-Way ANCOVA (w Interaction) add-in

julian​

[#10]

Hi Julian,

I used v03 but got the same output as before.

Hillary.

From: julian

Sent: Friday, May 27, 2016 12:09 AM

To: Hillary Voet <hillary.voet@mail.huji.ac.il>

Subject: Re: - comparison of slopes

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[#11]

Hi Julian,

It seems to be the values that are problematical. When I give the

categories names a1, a2, etc. I get the expected output.

Hillary.

From: julian

Sent: Friday, May 27, 2016 12:09 AM

To: Hillary Voet <hillary.voet@mail.huji.ac.il>

Subject: Re: - comparison of slopes

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