#Set working directory
setwd("/Users/Shared/WD/Rdirectory")  #Change this pathname to wherever you saved the example data files
#Print current working directory
getwd()

#Example 1 contains simulated weights (lbs) of men

#If so desired, you may save output in an external file named example1.txt
sink("example1.txt", append=FALSE, split=TRUE)
#Read data file into R as a vector
example1 = scan("example1.dat")
#The sink command does not output the commands so it is helpful to print what is output.  Note that source("intro.R", echo=TRUE) will include the commands and output.
#Print the words "Raw data" to the screen and output
print("Raw data")
#Print data
example1
print("Mean")
#Calculate the sample mean and assign it to an object named xbar
xbar=mean(example1)
#Print xbar
xbar
#You do not have to assign the function to an object to see the value
print("Standard deviation")
sd(example1)
#Stop output to example1.txt
sink()


#Example 2 contains simulated average daily temperatures in State College, PA during May and November

#Read data file into R as a data frame 
example2  = read.table("example2.csv", header=T, sep=",")
#Print data
example2
#Creates a jpg of graphical output; sink() will not output graphs
jpeg("example2.jpg")
#To print multiple graphs on a page, split the plotting window into 2 rows and 2 columns
par(mfrow=c(2,2))
#Plot a histogram of May
hist(example2$may)
#Plot a histogram of November
hist(example2$november)
#Stop output to example2.jpg
dev.off()
#Note that R is case-sensitive.  Both of the following commands will produce errors due to case:
Hist(example2$may)
#Error in eval.with.vis(expr, envir, enclos) : could not find function "Hist"
hist(example2$May)
#Error in hist.default(example2$May) : 'x' must be numeric
#Because Hist(example2$may) produced an error, R stopped running code from this program.  hist(example2$May) therefore was not sourced.  I copied the error reported by R for your reference.  By the reported error, it is not clear that the problem is simply a matter of case; it is only clear that there is a problem.