1 The software package and Rstudio

2 Create a directory on your hard drive

Create a directory on your hard drive to be used on this course. Here I have created one on my desktop called ipsR – but any directory name is fine.

3 Startup Rstudio

by clicking the Rstudio icon.

4 Create a project

Choose the directory that you just created under step 1. See the figure below:

You only need to create the project once. When you startup Rstudio the next time, the system should automatically open up inside this project that you created. If not, or if you closed the project, you can open it again:

You can get back to your default directory (if you were using R before then) any time by selecting close project in the above menu. If you have any difficulty with project installation watch this introductory video.

5 Install packages

In the Rstudio console window, install the following packages (may take a few minutes). You only need to do this once:

# install the following packages
install.packages(c("Rcpp", "remotes", "knitr", 
                   "tidyverse", "magrittr",
                   "rmarkdown", "emuR", "gridExtra", 
                   "emmeans", "broom", "lmerTest", 
                   "pbkrtest", "MuMIn", "wrassp", "ezANOVA"))

More information: installation of R packages

Should the above result in the error message installation of package had non-zero exit status, then it means that installation has failed. For Windows, you might then additionally have to install Rtools. Für MacOS you might need to install/reset the XCode command-line tools. For this purpose, open a Mac terminal window and execute the following:

xcode-select --install
# Should the R packages installation still not work:
xcode-select --reset

6 Starting and quitting Rstudio

A session starts when RStudio is opened. A session is terminated with Session > Quit Session in the main toolbar or with q() or Strg+Q or Ctrl+Q. The session also ends automatically when you quit RStudio. Verify that you can start and quit from Rstudio. You will then be asked whether you want to save the workspace image. For this course, please never save the workspace i.e. Don't save.

7 For students of P 12.1 Programmiersprache R und P 12.2 Statistik

From this website, download the Rmd file under 1.1 Objects and their manipulation and save it to an easily accessible directory of your choice on your computer. After starting up Rstudio, load this file with filename 01_Rintro.Rmd into Rstudio. One of ways to do this is with File -> Open File. You should now be able to see the file 01_Rintro.Rmd in Rstudio.

8 Learning R: the community

There is a very large and helpful R community that will make learning R easier for you. Here are a few useful links and commands in case you get stuck:

# for e.g. one of the libraries from tidyverse
vignette("dplyr")
?getwd
help("getwd")
apropos("spline")
install.packages('swirl')
library(swirl)
swirl()

ggplot2 is both a well-known and popular program for creating plots. There’s plenty of help available for ggplot2 from the R community. Here are some useful links for creating graphics:

9 Statistics in R: Literature

If you need more information using statistics in R, the following are recommended:

10 R Markdown

R Markdown is a type of text document in which so called code snippets can be embedded and executed. Typically R Markdown files contain more text than code. An R markdown file can be created with File > New File > R Markdown and should be saved with the extension .Rmd. It can then be converted or knitted into other formats including HTML. This conversion is done by clicking on the wool icon next to Knit. Alternatively:

library(rmarkdown)
# where x.Rmd is the document to be knitted
render("x.Rmd")

This entire course makes use of R markdown. You can convert the .Rmd files into HTML as follows.

For example, download and copy setup.Rmd (the file you are currently reading) into your project directory from here into your project directory.

Also download and unpack into the same directory the images that are needed for this conversion.

Your project directory should now include a folder called img and any number of .Rmd files as shown here:

Open setup.Rmd in Rstudio (e.g. from the toolbar, File > Open File and choose setup.Rmd) and then click the Knit button as shown below in order to create the corresponding HTML file which will also be stored in your project directory:

You should be able to create HTML files yourself for any .Rmd files on this course. This is also a useful verification that all the code can be executed on your computer.

Here are a few further brief pointers on using Markdown.

You can run pieces of code known as code-snippets using the green arrow on the right as shown in the figure below.

Some information about creating text for your own markdown document is as follows:

# Heading: One hashtag gives the largest heading; the greater the number of hashtags the smaller (the more embedded) heading.

**bold**: can be marked with double asterisks before and after the text to be placed in bold.

*italics*: as above but with a single asterisk

`code`: single backslashes can be used to denote variables or code within running text.

```: Three backslashes mark the beginning and end of code - see the above figure.

More information see the Cheatsheet for R Markdown (esp. p. 2, left column).

11 For users of EmuR

11.1 Libraries

Load the emuR and wrassp libraries:

library(emuR)
library(wrassp)

11.2 Default browser

Set your default browser to Google Chrome. This is necessary in order to display the Emu web application from R.

11.3 Verification

Verify that everything works by entering the following commands to the console.

# download a demo database
create_emuRdemoData(dir = tempdir())
# load it
ae = load_emuDB(file.path(tempdir(), "emuR_demoData", "ae_emuDB"))
# look at it
serve(ae, useViewer=F)
# close the browser window to carry on

The third command serve(ae, useViewer=F) should produce the following image in your browser: