leveneTest

0th

Percentile

Levene's Test

Computes Levene's test for homogeneity of variance across groups.

Keywords
htest
Usage
leveneTest(y, ...)
## S3 method for class 'formula':
leveneTest(y, data, ...)
## S3 method for class 'lm':
leveneTest(y, ...)
## S3 method for class 'default':
leveneTest(y, group, center=median, ...)
Arguments
y
response variable for the default method, or a lm or formula object. If y is a linear-model object or a formula, the variables on the right-hand-side of the model must all be factors and must be completely
group
factor defining groups.
center
The name of a function to compute the center of each group; mean gives the original Levene's test; the default, median, provides a more robust test.
data
a data frame for evaluating the formula.
...
arguments to be passed down, e.g., data for the formula and lm methods; can also be used to pass arguments to the function given by center (e.g., center=mean and trim=0.1
Value

  • returns an object meant to be printed showing the results of the test.

Note

adapted from a response posted by Brian Ripley to the r-help email list.

References

Fox, J. (2008) Applied Regression Analysis and Generalized Linear Models, Second Edition. Sage. Fox, J. and Weisberg, S. (2011) An R Companion to Applied Regression, Second Edition, Sage.

Aliases
  • leveneTest
  • leveneTest.formula
  • leveneTest.lm
  • leveneTest.default
Examples
with(Moore, leveneTest(conformity, fcategory))
with(Moore, leveneTest(conformity, interaction(fcategory, partner.status)))
leveneTest(conformity ~ fcategory*partner.status, data=Moore)
leveneTest(lm(conformity ~ fcategory*partner.status, data=Moore))
leveneTest(conformity ~ fcategory*partner.status, data=Moore, center=mean)
leveneTest(conformity ~ fcategory*partner.status, data=Moore, center=mean, trim=0.1)
Documentation reproduced from package car, version 2.0-20, License: GPL (>= 2)

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