# This is an Splus command script
# written by Ashton Shortridge, April 6, 2000

# First some simple stuff #

1+2               # S-Plus can be a calculator!
big <- 45 * 59    # Create an object called big. Assign 45*59 to it.
big/20            # Prints result but does not affect value of big
smaller <- big/40 # New assignment
big <- smaller/55 # Assign a new value to big
big <- big / smaller  # Splus doesn't choke on this sort of thing.
big               # prints the new value for big.

rm(big)     # erase the big object
rm(smaller) # erase the smaller object. It's just a little smaller now!


# Now some more complicated stuff

index <- c(1:50)  # Assignment statement. Object (vector) named "index" gets values 1-50

noisy<-rnorm(50,100,50)  #Object (vector) "noisy" gets 50 values randomly drawn from a normal distribution with m=100, sd=50

quiet<-rnorm(50,100,10)
ntrend_noisy + index  # underscore "_" is same as <-
qtrend_quiet+index    # Splus knows how to add vectors. Spacing not important.

t.test(ntrend,qtrend, var.equal=F)  # see help on this complex function

# You can try to interpret results of the T-test from the output.
# You could also write the output as an object by assignment.

plot(ntrend)    #opens a graphics window and does the plot
points(qtrend, pch=3)  #add some diff't points to the plot
title(main="Noisy vs Quiet data")

two.trends_as.data.frame(cbind(ntrend,qtrend))  #This is a compound expression.
		# cbind creates a matrix object w/ the two vectors
		# as.data.frame turns the matrix into a data frame

rm(index)  #erase the index object
rm(qtrend,ntrend,quiet,noisy) #erase lots more stuff in one line