Welcome to Using R for Statistics. This book was written for anyone who wants to use R to analyze data and create statistical plots. It is suitable for those with little or no experience with R, and aims to get you up and running quickly without having to learn all the details of programming.

About R

R is a statistical analysis and graphics environment and also a programming language. It is command-driven and very similar to the commercially produced S-Plus® software. R is known for its professional-looking graphics, which allow complete customization.

R is open-source software and free to install under the GNU general public license. It is written and maintained by a group of volunteers known as the R core team.

The base software is supplemented by over 5,000 add-on packages developed by R users all over the world, many of whom belong to the academic community. These packages cover a broad range of statistical techniques including some of the most recently developed and niche purpose. Anyone can contribute add-on packages, which are checked for quality before they are added to the collection.

At the time of writing, the current version of R is 3.1.0.

What You Will Learn

This book is designed to give straightforward, practical guidance for performing popular statistical methods in R. The programming aspect of R is explored only briefly.

After reading this book you will be able to:

• navigate the R system
• enter and import data
• manipulate datasets
• calculate summary statistics
• create statistical plots and customize their appearance
• perform hypothesis tests such as the t-test and analysis of variance
• build regression models
• access additional functionality with the use of add-on packages
• create your own functions

Knowledge Assumed

Although this book does include some reminders about statistics methods and examples demonstrating their use, it is not intended to teach statistics. Therefore, you will require some previous knowledge. You should be able to select the most appropriate statistical method for your purpose and interpret the results. You should also be familiar with common statistical terms and concepts. If you are unsure about any of the methods that you are using, I recommend that you use this book in conjunction with a more detailed book on statistics.

No prior knowledge of R or of programming is assumed, making this book ideal if you are more accustomed to working with point-and-click style packages. Only general computer skills and a familiarity with your operating system are required.

Conventions Used in This Book

This book uses the following typographical conventions:

• Fixed width font is used to distinguish all R commands and output from the main text.
• Normal fixed width font is used for built-in R function names, argument names, syntax, specific dataset and variable names, and any other parts of the commands that can be copied verbatim.
• Slanted fixed width font is used for generic dataset and variable names and any other parts of the commands that should be replaced with the user’s own values.
• Often it has not been possible to fit a whole command into the width of the page. In these cases, the command is continued on the following line and indented. Where you see this, the command should still be entered into the console on a single line.
• Text boxes, which are separate from the main text, contain reminders of statistical theory or methods.
• Practical examples are presented in separate numbered sections.

Datasets Used in This Book

A large number of example datasets are included with R, and these are available to use as soon as you open the software. This book makes use of several of these datasets for demonstration purposes.

There are also a number of additional datasets used throughout the book, details of which are given in the Appendix C. They are available to download at www.apress.com/9781484201404.

Contact the Author

If you have any suggestions or feedback, I would love to hear from you. You can email me at [email protected].