# Statistical Analysis: an Introduction using R/R/Packages

Some packages should always be available within R, and a number of these are automatically loaded at the start of an R session. These include the "base" package (which is where the max and sqrt functions are defined), the "utils" package (which is where RSiteSearch and citation are defined), the "graphics" package (which allows plots to be generated), and the "stats" package (which provides a broad range of statistical functionality). In total, the default packages allow you to do a considerable amount of statistics.
> library(datasets) #Load the datasets package (actually, it has probably been loaded already) > cars #Display one of the datasets: see ?car for more information
1 4 2 2 4 10 3 7 4 4 7 22 5 8 16 6 9 10 7 10 18 8 10 26 9 10 34 10 11 17 11 11 28 12 12 14 13 12 20 14 12 24 15 12 28 16 13 26 17 13 34 18 13 34 19 13 46 20 14 26 21 14 36 22 14 60 23 14 80 24 15 20 25 15 26 26 15 54 27 16 32 28 16 40 29 17 32 30 17 40 31 17 50 32 18 42 33 18 56 34 18 76 35 18 84 36 19 36 37 19 46 38 19 68 39 20 32 40 20 48 41 20 52 42 20 56 43 20 64 44 22 66 45 23 54 46 24 70 47 24 92 48 24 93 49 24 120 50 25 85 > library(vioplot) #Try loading the "vioplot" package: this will probably fail as it is not installed by default Error in library(vioplot) : there is no package called 'vioplot' > install.packages("vioplot") #This is one way of installing the package. There are other ways too. also installing the dependency ‘sm’
trying URL 'http://cran.uk.r-project.org/bin/macosx/universal/contrib/2.8/sm_2.2-3.tgz' Content type 'application/x-gzip' length 306188 bytes (299 Kb) opened URL
downloaded 299 Kb
trying URL 'http://cran.uk.r-project.org/bin/macosx/universal/contrib/2.8/vioplot_0.2.tgz' Content type 'application/x-gzip' length 9677 bytes opened URL
downloaded 9677 bytes
The downloaded packages are in /tmp/RtmpR28hpQ/downloaded_packages > library(vioplot) #This should now work Loading required package: sm Package `sm', version 2.2-3; Copyright (C) 1997, 2000, 2005, 2007 A.W.Bowman & A.Azzalini type help(sm) for summary information > example(vioplot) #produces some pretty graphics. Don't worry about what they mean for the time being
vioplt> # box- vs violin-plot vioplt> par(mfrow=c(2,1))
vioplt> mu<-2
vioplt> si<-0.6
vioplt> bimodal<-c(rnorm(1000,-mu,si),rnorm(1000,mu,si))
vioplt> uniform<-runif(2000,-4,4)
vioplt> normal<-rnorm(2000,0,3)
vioplt> vioplot(bimodal,uniform,normal) Hit <Return> to see next plot:
vioplt> boxplot(bimodal,uniform,normal)
vioplt> # add to an existing plot vioplt> x <- rnorm(100)
vioplt> y <- rnorm(100)
vioplt> plot(x, y, xlim=c(-5,5), ylim=c(-5,5)) Hit <Return> to see next plot:
vioplt> vioplot(x, col="tomato", horizontal=TRUE, at=-4, add=TRUE,lty=2, rectCol="gray")
vioplt> vioplot(y, col="cyan", horizontal=FALSE, at=-4, add=TRUE,lty=2)
There are several other ways of installing packages. If you start R by typing "R" on a unix command-line, then you can install packages by running "R CMD INSTALL packagename" from the command-line instead (see ?INSTALL). If you are running R using a graphical user interface (e.g. under Macintosh or Windows), then you can often install packages by using on-screen menus. Note that these methods may not install other, dependent packages.

## Notes

* ↑ Actually, the details are slightly more complex, depending on whether there is a default location to install the packages, see ?install.packages