#QUALITATIVE PREDICTORS
# READ STRUCTURED DATA TABLE
K=read.table("c:/2008LinearModelsData/InsInnovationR.txt")
K
attach(K)
options(digits=7)

#FITTING FULL MODEL WITH FACTOR
FM=lm(Y~X+FAC)
summary(FM)
anova(FM)

#LOOKING AT FACTORS

#READ STRUCTURED DATA TABLE WITH NUMERIC CODED FACTOR
K1=read.table("c:/2008LinearModelsData/SurgicalUnit1R.txt")
K1
attach(K1)

#SETTING VARIABLE X7 AS A FACTOR **FOR NUMERIC CODES**
X7=factor(X7c)

#VIEWING CONTRAST & DESIGN MATRIX X
FM=lm(Y~X1+X2+X3+X4+X5+X6+X7)
contrasts(X7)
model.matrix(FM)
summary(FM)
anova(FM)

#READ STRUCTURED DATA TABLE WITH TEXT CODED FACTOR
K2=read.table("c:/2008LinearModelsData/SurgicalUnit2R.txt")
K2
detach(K1)
attach(K2)

#VIEWING CONTRAST & DESIGN MATRIX X
FM=lm(Y~X1+X2+X3+X4+X5+X6+X7)
contrasts(X7)
model.matrix(FM)
summary(FM)
anova(FM)

#READ STRUCTURED DATA TABLE WITH 
#INDICATOR CODEs FOR FACTOR
K3=read.table("c:/2008LinearModelsData/SurgicalUnit3R.txt")
K3
detach(K2)
attach(K3)

#DIRECT CALCULATION WITH CONTRAST MATRIX
X7c=cbind(X7n,X7m,X7h)
X7c
Ct=contr.treatment(3)
Ct

#MAKING CODED FACTOR
X7=X7c%*%Ct #MATRIX MULTIPLICATION
X7

#VIEWING CONTRAST & DESIGN MATRIX X
FM=lm(Y~X1+X2+X3+X4+X5+X6+X7)
model.matrix(FM)
summary(FM)
anova(FM)

#DIFFERENT CONTRASTS

#TREATMENT CONTRASTS (DEFAULT)
X7=factor(K1$X7c)
contrasts(X7)
FM=lm(Y~X1+X2+X3+X4+X5+X6+X7)
model.matrix(FM)
summary(FM)
anova(FM)

#SETTING HELMERT CONTRASTS
contrasts(K2$X7)=contr.helmert
FM=lm(Y~X1+X2+X3+X4+X5+X6+K2$X7)
contrasts(K2$X7)
model.matrix(FM)
summary(FM)
anova(FM)

#SETTING SUM CONTRASTS
contrasts(K2$X7)=contr.sum
FM=lm(Y~X1+X2+X3+X4+X5+X6+K2$X7)
contrasts(K2$X7)
model.matrix(FM)
summary(FM)
anova(FM)