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Last data update: 2014.03.03

R: Multiple comparisons, scheffe

scheffe.test

R Documentation

Multiple comparisons, scheffe

Description

Scheffe 1959, method is very general in that all possible contrasts can be tested for significance and confidence intervals can be constructed for the corresponding linear. The test is conservative.

Usage

scheffe.test(y, trt, DFerror, MSerror, Fc, alpha = 0.05, 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
`MSerror`	Mean Square Error
`Fc`	F Value
`alpha`	Significant level
`group`	TRUE or FALSE
`main`	Title
`console`	logical, print output

Details

It is necessary first makes a analysis of variance.

Value

`y`	class (aov or lm) or vector numeric
`trt`	constant (only y=model) or vector alfanumeric
`DFerror`	Numeric
`MSerror`	Numeric
`Fc`	Numeric
`alpha`	Numeric
`group`	Logic
`main`	Text

Author(s)

Felipe de Mendiburu

References

Examples

library(agricolae)
data(sweetpotato)
model<-aov(yield~virus, data=sweetpotato)
comparison <- scheffe.test(model,"virus", group=TRUE,console=TRUE,
main="Yield of sweetpotato\nDealt with different virus")
# Old version scheffe.test()
df<-df.residual(model)
MSerror<-deviance(model)/df
Fc<-anova(model)["virus",4]
comparison <- with(sweetpotato,scheffe.test(yield, virus, df, MSerror, 
Fc, group=TRUE,main="Yield of sweetpotato. Dealt with different virus"))