Computes Levene's test for homogeneity of variance across groups.
leveneTest(y, ...)
# S3 method for formula
leveneTest(y, data, ...)
# S3 method for lm
leveneTest(y, ...)
# S3 method for default
leveneTest(y, group, center=median, ...)returns an object meant to be printed showing the results of the test.
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.
factor defining groups.
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.
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).
John Fox jfox@mcmaster.ca; original generic version contributed by Derek Ogle
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.
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)
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