pairComp: Pairwise comparisons between the numeric elements of a vector

In statforbiology: Tools for Data Analyses in Biology

Pairwise comparisons between the numeric elements of a vector

Description

This function provides pairwise comparisons between the element of a vector, as long as a variance-covariance matrix is also provided

Usage

pairComp(parm, vcovMat, nams = NULL, dfr = NULL, adjust = "none",
         level = 0.05, Letters = c(letters, LETTERS, "."),
         reversed = FALSE)

Arguments

parm	A (possibly named) vector of estimates
vcovMat	Variance-covariance matrix for the estimates
nams	A character vector of parameter names (optional). If it is not provided and if 'parm' is not a named vectors, numbers '1:length(parm)' are used.
dfr	An optional number of residual degrees of freedom (defaults to Inf)
adjust	A multiplicity adjustment method as in 'multcomp'. Defaults to "none".
level	Protection level for compact letter display
Letters	Vector of distinct characters (or character strings) used to connect levels that are not significantly different. They should be recogizable when concatenated. The default behaviour is to use the small letters, followed by the capital letters. See help for 'multcompView::multcompLetters()' for futher detail)
reversed	logical. Should the order of means/letters be decreasing? Defaults to FALSE, which means that the means and letters are in increasing order)

Value

Returns a list with the following elements

Pairs	A dataframe of pairwise comparisons
Letters	A dataframe with compact letter display

Author(s)

Andrea Onofri

References

Onofri A. (2020) The broken bridge between biologists and statisticians: a blog and R package, Statforbiology, IT, web: https://www.statforbiology.com

Examples

# library(devtools)
# install_github("OnofriAndreaPG/aomisc")
library(statforbiology)
data(metamitron)

#Fit nls grouped model
modNlin <- nls(Conc ~ A[Herbicide] * exp(-k[Herbicide] * Time),
               start=list(A=rep(100, 4), k=rep(0.06, 4)),
               data=metamitron)
tab <- summary(modNlin)
tab

# Retreive infos and make comparisons
coefs <- coef(modNlin)[5:8]
vcovMat <- vcov(modNlin)[5:8, 5:8]
cp <- pairComp(coefs, vcovMat, dfr = tab$df[2],
               adjust = "none", reversed = FALSE)
cp$Letters
cp$pairs

statforbiology documentation built on Oct. 30, 2024, 9:13 a.m.