LSD.test: Multiple comparisons, "Least significant difference" and...

In laynelv/isenso: intelligent sensory tests: a package of R programming for food sensory & consumer evaluations.

Description

Multiple comparisons of treatments by means of LSD and a grouping of treatments. The level by alpha default is 0.05. Returns p-values adjusted using one of several methods

Usage

LSD.test(y, trt, DFerror, MSerror, alpha = 0.05, p.adj=c("none","holm","hommel",
"hochberg", "bonferroni", "BH", "BY", "fdr"), group=TRUE, main = NULL,console=FALSE)

Arguments

y	model(aov or lm) or answer of the experimental unit
trt	Constant( only y=model) or vector treatment applied to each experimental unit
DFerror	Degrees of freedom of the experimental error
MSerror	Means square error of the experimental
alpha	Level of risk for the test
p.adj	Method for adjusting p values (see p.adjust)
group	TRUE or FALSE
main	title of the study
console	logical, print output

Details

For equal or different repetition. p.adj = "holm", "hommel", "hochberg", "bonferroni", "BH", "BY", "fdr". see p.adjust() p-adj ="none" is t-student. p-adj ="hommel" is not applied in this test.

Value

y	class (aov or lm) or vector numeric
trt	constant (only y=model) or vector alfanumeric
DFerror	Numeric
MSerror	Numeric
alpha	Numeric
p.adj	text, see p.adjust
group	Logic
main	Numeric

Author(s)

Felipe de Mendiburu

References

Steel, R.; Torri,J; Dickey, D.(1997) Principles and Procedures of Statistics A Biometrical Approach. pp178.

See Also

HSD.test, waller.test, SNK.test , bar.err, bar.group,duncan.test

Examples

library(agricolae)
data(sweetpotato)
model<-aov(yield~virus, data=sweetpotato)
out <- LSD.test(model,"virus", p.adj="bonferroni")
#stargraph
bar.group(out$groups,ylim=c(0,45),density=4,border="blue")
#endgraph
# Old version LSD.test()
df<-df.residual(model)
MSerror<-deviance(model)/df
out <- with(sweetpotato,LSD.test(yield,virus,df,MSerror, p.adj="bonferroni",
group=FALSE))
#stargraph
# Variation range: Max - Min
bar.err(out$means,variation="range",ylim=c(0,44),bar=FALSE,col=0)
#endgraph
LSD.test(model,"virus",p.adj="bon",console=TRUE)

laynelv/isenso documentation built on May 20, 2019, 8:26 p.m.