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CBC/Hb - Covariates in the alpha file

Hello everyone,

I am really new to CBC/HB and I conducted an analysis with three conditions. I put the conditions as Covariates.
When I checked the alpha file, I saw that there are columns for intercept for each attribute level, for condition 1 and condition 2, but I don't unterstand why condition 3 is not shown or do I interpret it wrong.
I want to conduct a t-test to see if there are significant differences for price in the upper models.

Maybe you could help me.

Best regards
asked May 28, 2017 by JanaJardir2 (235 points)
retagged Jun 19, 2017 by Walter Williams

1 Answer

+1 vote
Best answer
Level 3 respondents for your covariate (the last level of any categorical covariate) are represented in the intercept values.  Levels 1 and 2 respondents are represented by the intercept values plus the alpha values shown in the alpha file.

So, for example, if for Brand 1 the intercept value was +1 and the covariate value for level 1 respondents was +2, the total alpha value (mean population parameter) for level 1 respondents would be 1+2=3.
answered May 29, 2017 by Bryan Orme Platinum Sawtooth Software, Inc. (138,915 points)
selected May 30, 2017 by JanaJardir2