The function implements purely nonparametric Steel-type multiple contrast tests for either making many-to-one (Dunnett-type) or all pairwise (Tukey-type) comparisons. Null hypotheses are formulated in terms of the distribution functions.
steel(
formula,
data,
control = NULL,
alternative = c("two.sided", "less", "greater"),
info = TRUE,
correlation = TRUE
)
A model formula
object. The left hand side
contains the response variable and the right hand side contains
the factor variable of interest.
A data.frame, list or environment containing the variables in
formula
. The default option is NULL
.
Specification of the control group for making many-to-one-comparisons. If NULL, all-pairwise comparisons are performed.
Specification of the direction of the alternative. Default is two-sided.
Logical. If TRUE, additional output information and explanation is printed to the console.
Logical. If TRUE, the correlation matrix is printed.
A list containing the following components:
Groups and sample sizes of the data
Data frame containing the test results (comparison, relative effect estimator, standard error, test statistic and p-value.)
Estimated correlation matrix
The steel() function calculates the Steel-type tests as explained by Munzel, U., Hothorn, L. A. (2001). A unified approach to simultaneous rank test procedures in the unbalanced one-way layout. Biometrical Journal: Journal of Mathematical Methods in Biosciences, 43(5), 553-569.
Brunner, E., Bathke, A.C., Konietschke, F. Rank and Pseudo-Rank Procedures for Independent Observations in Factorial Designs. Springer International Publishing, 2018.
Munzel, U., Hothorn, L. A. (2001). A unified approach to simultaneous rank test procedures in the unbalanced one-way layout. Biometrical Journal: Journal of Mathematical Methods in Biosciences, 43(5), 553-569.
Konietschke, F., Hothorn, L. A., Brunner, E. (2012). Rank-based multiple test procedures and simultaneous confidence intervals. Electronic Journal of Statistics, 6, 738-759.
# NOT RUN {
data(Muco)
model.oneway <- steel(HalfTime ~ Disease, data = Muco,info=TRUE,correlation=TRUE)
# }
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