#Basic Commands x <- c(1,2,3,4,5) x x = c(5,3,9) x y = c(3,7,2) class(x) length(x) x+y z = x+y z ls() rm(z) ls() rm(list=ls()) ls() ?matrix x = matrix(data=c(1,2,3,4), nrow=2, ncol=2) x x = matrix(c(1:6), 2, 2) x matrix(c(1:6), 2, 2, byrow=TRUE) sqrt(x) x^2 x = rnorm(50) x x = rnorm(50) x set.seed(123) x = rnorm(50) x set.seed(123) x = rnorm(50) x y = x+rnorm(50, mean=50, sd=.1) cor(x,y) #Gaphics plot(x,y) plot(x,y, xlab="x-axis", ylab="y-axis", main="Plot of X vs Y") ?contour x = seq(-pi, pi, length=50) y=x f=outer(x,y, function(x,y) cos(y)/(1+x^2)) contour(x,y,f) contour(x,y,f, nlevels=45, add=T) fa = (f-t(f))/2 contour(x,y,fa,nlevels=15) image(x,y,fa) persp(x,y,fa) persp(x,y,fa, theta=30) #Indexing Data A = matrix(1:16,4,4) A A[2,3] A[c(1,3),c(2:4)] A[2,] A[,2] A[,1:2] A[-3,] dim(A) A = A[-4,] dim(A) dim(A)[1] #Loading Data and Plotting gallup = read.csv("http://www...