agricolae (version 1.2-0)

scheffe.test: 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

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

Details

It is necessary first makes a analysis of variance.

References

Robert O. Kuehl. 2nd ed. Design of experiments. Duxbury, copyright 2000. Steel, R.; Torri,J; Dickey, D.(1997) Principles and Procedures of Statistics A Biometrical Approach. pp189

See Also

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

Examples

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