#MULTIVARIATE DATA SUMMARY STATISTICS & DIAGNOSTICS
#READ DATA:
M=read.table("c:/DATA/Multivariate/iris.txt")
M

#INDICES:
M[5,2]

#MATRIX DIMENSIONS:
n=nrow(M)
n
p=ncol(M)
p

summary(M)

#MEAN VECTOR:
M=subset(M,select=c("Sepal.Length","Sepal.Width","Petal.Length","Petal.Width"))
Mbar=mean(M)
Mbar

#COVARIANCE MATRIX:
cov(M)

#CORRELATION MATRIX:
cor(M)

#STANDARDIZED DATA MATRIX:
Ms=scale(M)
Ms

#COVARIANCE MATRIX OF STANDARDIZED DATA:
cov(Ms)

#DIAGNOTIC PLOTS:
plot(M)

library(car)
scatterplotMatrix(M)

library(lattice)
attach(iris)
xyplot(Sepal.Length~Sepal.Width|Species,
   main="Sepal.Length vs Sepal.Width",
   ylab="Sepal.Width", xlab="Sepal.Length")