is an option for statistical functions such as LinearModelFit that specifies which variables should be treated as having discrete values specified by names.


NominalVariables
is an option for statistical functions such as LinearModelFit that specifies which variables should be treated as having discrete values specified by names.
Details

- Possible settings for NominalVariables include:
-
Automatic automaticaly detect nominal variables All treat all variables as nominal None treat no variables as nominal {v1,v2,…} treat the variables vi as nominal - When NominalVariables->Automatic, different methods are used to detect nominal variables. In functions returning FittedModel[…], variables with non-numeric data values are treated as nominal.
- In linear models, a nominal variable v with possible values s1, s2, … is represented as a collection of variables with values 1 or 0 corresponding to each case v==si.
Examples
open all close allBasic Examples (1)
Scope (2)
Automatically select nominal variables:
Specify nominal variables in GeneralizedLinearModelFit:
With LogitModelFit:
With ProbitModelFit:
Applications (3)
Compute the model estimates for the three groups:
Fit a two‐way ANOVA model with interaction term:
Compute estimates for each cell:
Visualize curves for the three x categories and label using Tooltip:
Related Guides
Text
Wolfram Research (2008), NominalVariables, Wolfram Language function, https://reference.wolfram.com/language/ref/NominalVariables.html (updated 2014).
CMS
Wolfram Language. 2008. "NominalVariables." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2014. https://reference.wolfram.com/language/ref/NominalVariables.html.
APA
Wolfram Language. (2008). NominalVariables. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/NominalVariables.html
BibTeX
@misc{reference.wolfram_2025_nominalvariables, author="Wolfram Research", title="{NominalVariables}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/NominalVariables.html}", note=[Accessed: 08-August-2025]}
BibLaTeX
@online{reference.wolfram_2025_nominalvariables, organization={Wolfram Research}, title={NominalVariables}, year={2014}, url={https://reference.wolfram.com/language/ref/NominalVariables.html}, note=[Accessed: 08-August-2025]}