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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
Details and Options Details and Options
Examples  
Basic Examples  
Scope  
Applications  
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NominalVariables

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:
  • Automaticautomaticaly detect nominal variables
    Alltreat all variables as nominal
    Nonetreat 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

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Basic Examples  (1)

Define some data:

Fit the data, treating the first variable as a nominal variable:

See the functional form:

Treat all variables as nominal:

Scope  (2)

Automatically select nominal variables:

Specify nominal variables in GeneralizedLinearModelFit:

With LogitModelFit:

With ProbitModelFit:

Applications  (3)

Fit a one‐way ANOVA model:

Obtain the ANOVA table:

Compute the model estimates for the three groups:

Fit a two‐way ANOVA model with interaction term:

Obtain the ANOVA table:

Compute estimates for each cell:

Results in a table:

Fit an ANCOVA model:

Visualize curves for the three x categories and label using Tooltip:

Wolfram Research (2008), NominalVariables, Wolfram Language function, https://reference.wolfram.com/language/ref/NominalVariables.html (updated 2014).

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: 28-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: 28-August-2025]}