In PROC LOGISTIC with CLASS variables, which parameterization uses the last alphabetically sorted category as the reference by default?
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Short Explanation and Infographic
Here's the deal — b is correct because the default CLASS variable parameterization in PROC LOGISTIC uses reference coding (PARAM=REF) where dummies compare to the last alphabetically sorted category. A (PARAM=GLM) is effect coding used in PROC GLM.
Full explanation below image
Full Explanation
B is correct because the default CLASS variable parameterization in PROC LOGISTIC uses reference coding (PARAM=REF) where dummies compare to the last alphabetically sorted category. A (PARAM=GLM) is effect coding used in PROC GLM. C (PARAM=DEVIATION) compares each level to the grand mean. D (PARAM=ORTHPOLY) uses polynomial contrasts for ordered variables.