car (version 3.0-12)

# leveneTest: Levene's Test

## Description

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

## 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.

## 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.

## 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)
# }
```