leveneTest

0th

Percentile

Levene's Test

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

Keywords
htest
Usage
leveneTest(y, ...)
# S3 method for formula
leveneTest(y, data, ...)
# S3 method for lm
leveneTest(y, ...)
# S3 method for 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 crossed.

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 specify the 10% trimmed mean).

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. (2016) Applied Regression Analysis and Generalized Linear Models, Third Edition. Sage.

Fox, J. and Weisberg, S. (2019) An R Companion to Applied Regression, Third Edition, Sage.

Aliases
  • leveneTest
  • leveneTest.formula
  • leveneTest.lm
  • leveneTest.default
Examples
# NOT RUN {
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 3.0-2, License: GPL (>= 2)

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