#Biostatistics 280

#BARTLETT'S TEST OF VARIANCE HOMOGENEITY
#ZAR EXAMPLE 10.13
ZAR=read.table("ZarEX10.13R.txt")
ZAR
attach(ZAR)
options(digits=12)
s1=sqrt(var(weights[feed=="1"]))
s1
s2=sqrt(var(weights[feed=="2"]))
s2
s3=sqrt(var(weights[feed=="3"]))
s3
s4=sqrt(var(weights[feed=="4"]))
s4
anova(lm(weights~factor(feed)))

#BARTLETT'S TEST:
bartlett.test(weights,feed)