levene_test: Levene's Test for Equality of Variance

Description Usage Arguments Details Value References See Also Examples

View source: R/levene.R

Description

This function performs the Levene's test for equality of variance.

Usage

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levene_test(data = NULL, x, groups, alpha = 0.05, modcv = FALSE)

Arguments

data

a data.frame

x

the variable in the data.frame or a vector on which to perform the Levene's test (usually strength)

groups

a variable in the data.frame that defines the groups

alpha

the significance level (default 0.05)

modcv

a logical value indicating whether the modified CV approach should be used.

Details

This function performs the Levene's test for equality of variance. The data is transformed as follows:

wij = | xij - mi |

Where mi is median of the ith group. An F-Test is then performed on the transformed data.

When modcv=TRUE, the data from each group is first transformed according to the modified coefficient of variation (CV) rules before performing Levene's test.

Value

Returns an object of class adk. This object has the following fields:

References

“Composite Materials Handbook, Volume 1. Polymer Matrix Composites Guideline for Characterization of Structural Materials,” SAE International, CMH-17-1G, Mar. 2012.

See Also

calc_cv_star()

transform_mod_cv()

Examples

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library(dplyr)

carbon.fabric.2 %>%
  filter(test == "FC") %>%
  levene_test(strength, condition)
##
## Call:
## levene_test(data = ., x = strength, groups = condition)
##
## n = 91          k = 5
## F = 3.883818    p-value = 0.00600518
## Conclusion: Samples have unequal variance ( alpha = 0.05 )

cmstatr documentation built on Sept. 30, 2021, 5:08 p.m.