# infer_levene_test: Levene's test for equality of variances In rsquaredacademy/inferr: Inferential Statistics

## Description

`infer_levene_test` reports Levene's robust test statistic for the equality of variances and the two statistics proposed by Brown and Forsythe that replace the mean in Levene's formula with alternative location estimators. The first alternative replaces the mean with the median. The second alternative replaces the mean with the 10

## Usage

 ```1 2 3 4 5``` ```infer_levene_test(data, ...) ## Default S3 method: infer_levene_test(data, ..., group_var = NULL, trim_mean = 0.1) ```

## Arguments

 `data` a `data.frame` or `tibble` `...` numeric; columns in `data` `group_var` factor; column in `data` `trim_mean` trimmed mean

## Value

`infer_levene_test` returns an object of class `"infer_levene_test"`. An object of class `"infer_levene_test"` is a list containing the following components:

 `bf` Brown and Forsythe f statistic `p_bf` p-value for Brown and Forsythe f statistic `lev` Levene's f statistic `p_lev` p-value for Levene's f statistic `bft` Brown and Forsythe f statistic using trimmed mean `p_bft` p-value for Brown and Forsythe f statistic using trimmed mean `avgs` mean for each level of the grouping variable `sds` standard deviations for each level of the grouping variable `avg` combined mean `sd` combined standard deviation `n` number of observations `n_df` numerator degrees of freedom `d_df` denominator degrees of freedom `levs` levels of the grouping variable `lens` number of observations for each level of the grouping variable `type` alternative hypothesis

## Deprecated Function

`levene_test()` has been deprecated. Instead use `infer_levene_test()`.

## References

Bland, M. 2000. An Introduction to Medical Statistics. 3rd ed. Oxford: Oxford University Press.

Brown, M. B., and A. B. Forsythe. 1974. Robust tests for the equality of variances. Journal of the American Statistical Association 69: 364–367.

Carroll, R. J., and H. Schneider. 1985. A note on Levene’s tests for equality of variances. Statistics and Probability Letters 3: 191–194.

## Examples

 ```1 2 3 4 5``` ```# using grouping variable infer_levene_test(hsb, read, group_var = race) # using variables infer_levene_test(hsb, read, write, socst) ```

rsquaredacademy/inferr documentation built on Oct. 4, 2018, 5:43 a.m.