[R] Scheffe test

[Marcelo]

Hi, Ana
try these source:
# Scheffe test, according Zar, J.H. (1984) Biostatistical Analysis.
# Englewood Cliffs: Prentice Hall.
# -----------------------------------------------------------------
 Scheffe1<- function(mxa,mxb,ms,na,nb,k,F) {
 # multiple comparision
 # DMSa=| meanXa- meanXb |
 # DMSc= critic value
 # if DMSa > DMSc --> reject H0
 # where mxa is mean of one group dataset,
 # and mxb is outher group dataset
 # na is number of samples for group a
 # nb is number of samples for group b
 # ms is mean square, F is F value, k is treatments
 result<-0
 DMSa<- abs(mxa-mxb)
 DMSc<- sqrt(((1/na)+(1/nb))*(k-1)*(ms)*(F))
 if (DMSa > DMSc) result<-c("rej. H0") else result<- c("ac. H0")
 return(cbind(result))
}

save as name.R in your work directory.
Hope this helps.

-- 
Oceanólogo Marcelo Alexandre Bruno 
#    Linux User: 124592    #
Pós-graduação Oceanografia Biológica
FUNDACAO UNIV. FEDERAL do RIO GRANDE
Departamento de Oceanografia
Lab. de Ecologia do Ictioplâncton
AV. ITÁLIA km 8 s/n - CARREIROS
Cx. Postal 474
96201-900 (0xx53) 2336529
Rio Grande - RS - BRAZIL