X <- read.csv("U:/public_html/588/Class1/CASE0101.csv", header = TRUE)     # replace by your own path here

V <- X[,1]    # all the scores in one "pile"
n1 <- 23
n2 <- 24

  V1 <- V[1:n1]
  V2 <-  V[(n1+1):(n1+n2)]  

# illustrates some descriptive stats

 mean(V1) 
 sd(V1) 
 quantile(V1,c(0.1, 0.25, 0.5, 0.75))   
 IQR(V1)




# illustrates some graphics

?boxplot

par(mfrow=c(2,2))      # 2x2 viewing window

boxplot(V ~ X[,2])      # get side-by-side boxplots with X[,2] as grouping variable     

c(min(V), max(V))

hist(V1, breaks = seq(5,30,by=2.5), ylim=c(0,8))
   hist(V2, breaks = seq(5,30,by=2.5), border="red", add=TRUE)

plot(density(V1), xlim=c(5,30), ylim=c(0,0.1))
  lines(density(V2),col="red")



data(faithful)         	# Old Faithful, a famous example of a bimodal distribution   
				# see e.g. Lavine, p. 121

X <- as.matrix(faithful) 
dim(X)
X[1:5,]                   # display only first 5 cases   

stem(X[,2])               # ways to display univariate distribution 
hist(X[,2])
plot( density(X[,2]) )