In this book, the Open Source statistical software package R 1 is used. R is available as Free Software under the terms of the Free Software Foundation’s GNU General Public License. It runs on a wide variety of UNIX platforms and similar systems (including FreeBSD and Linux), Windows and Mac OS X. More information is available on the website:


JGRThe JGR GUI 2;3 is used throughout this book. This GUI has two windows:

  1. Console
  2. Data Viewer

ConsoleconsoleThe console has an upper and lower window. In the lower window, R commands can be entered. The upper window shows the output.

Data ViewerdataviewerWhen no data are loaded, the data viewer shows icons to create new data or to open an existing (previously saved data set in RDA format, or Excel spreadsheet). If the data viewer is not visible, make sure the console window is active and select from the menu bar: Packages & Data and then Data Viewer.

R core team. A language and environment for statistical computing. R foundation for statistical computing. [Internet]. Vienna, Austria; 2010. Available from:
Fellows I. Deducer: A data analysis GUI for R. Journal of Statistical Software. 2012;49(8):1–15.
Helbig M, Urbanek S, Fellows I. JGR: JGR – Java GUI for R [Internet]. 2013. Available from: