# READ A STRUCTURED DATA TABLE
K=read.table("c:/2008LinearModelsData/DwaineDataFrame.txt")
K
attach(K)

# FIT LINEAR MODEL & REPORT
FM=lm(Y~X1+X2)
summary(FM)

#TRANSFORMATIONS OF DATA
n=length(Y)
Ks=scale(K,center=T,scale=T)
Ks
Kc=(1/sqrt(n-1))*Ks
Kc

#FIT TRANSFORMED DATA TO LINEAR MODEL
detach(K)
Kc=data.frame(Kc) #REFORMAT Kc AS A DATAFRAME
attach(Kc)
FMc=lm(Y~X1+X2)
summary(FMc)

#SCALE FUNCTION PROTOTYPE
#AND cov() cor() FUNCTIONS
#MEAN CENTER DATA:
Km=scale(K,center=T,scale=F)
Km
#STANDARDIZE DATA:
Ks=scale(K,center=T,scale=T)
Ks
#VARIANCE-COVARIANCE MATRIX:
S=cov(K)
S
#CORRELATION MATRIX:
R=cor(K)
R