Re: CTables Test of Significance

Posted by Bruce Weaver on Mar 28, 2017; 1:59am
URL: http://spssx-discussion.165.s1.nabble.com/CTables-Test-of-Significance-tp5734016p5734017.html

To summarize:

1. You have an ordinal dependent variable (rating).
2. You have one categorical explanatory variable (Jeep Model, with levels Compass, Wrangler, etc.).
3. Each respondent rates each model, so you have repeated measures.

One way to address your question is via GENLIN, using a multinomial error distribution with a cumulative logit (CUMLOGIT) link function, and with generalized estimating equations (GEE) to account for the correlated nature of the repeated measures.  (Another way would be to estimate a multilevel model via GENLINMIXED, with Jeep Model at level 1 and Respondent at level 2.)

I am not a CTABLES expert, but when I look it up in the FM, here is what I find under the heading of Significance Testing:

"Custom Tables can perform the chi-square test of independence and pairwise comparisons of column
proportions for tables that contain at least one category variable in both the rows and the columns."

The Chi-square test of independence assumes one observation per respondent, and is not appropriate for your repeated measures data.

HTH.

WillBaileyz wrote

Monday morning blank ...

I have a set of variables say different Jeep models like Compass, Wrangler,
Cherokee .... and for each a respondent does a rating from Very Satisfied -
Very Unsatisfied (Ordinal from 1 to 5) and want to do a test of sig between
the rating for each model.

For the life of me am blanked. In Ctables can set that x'tab up but since I
reposition the response codes from the brand to the column test of sig want
work

What am I missing

Running V24.0.0.1

 


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