Day 1: Introduction to R Statistical Analysis Software

Summer - 2024, University of Minnesota

Shunkei Kakimoto

Outline

• Introduction
• Motivation
  • What you can do with R?
  • How do we use R in course in APEC?
  • Basic knowledge about R and Rstudio (R 101)
• Plan for this course

About myself

• Shunkei Kakimoto
  • from Japan
  • 3rd year Ph.D. in Applied Economics (from this fall)
  • Area of interests: Environmental and Resource Economics, Water Economics, Groundwater Management, and Empirical analysis of climate change impact on agricultural production.
  • I was TA in Econometrics I and II (APEC 8211-12) and Micro Economics III and IV (APEC 8003-04)

Motivation to learn R

What is R?

It’s a programming language that can be used for a wide range of tasks.

• Data Manipulation: Cleaning, reshaping, merging datasets, etc.
• Various Analysis: Descriptive analysis, regression analysis, GIS, spatial analysis, machine learning, etc.
• Data visualization
• Great tool to communicate your results with others.
  • You can write a research paper, presentation slides, and even a book with R.

Note

• R is said to be slower programming language, but I don’t think that’s a general case. Some R packages (e.g., data.table for data wrangling, sf and terra for handling spatial data, etc.) are primarily written in other language such as C/C++ language, which makes their computation faster.

So, How R is used in the course of APEC?

• We use R in a series of Econometric courses (APEC 8211-8214)

Specifically,

• To conduct regression analysis (e.g., OLS, IV, FE, etc.)
• To conduct Monte Carlo simulation.
  • e.g., understand the difference in variance inference techniques.

Don’t worry!

• Even if you are not familiar or not confident in R, that’s okay! Basic knowledge of R is enough to conduct the tasks in the course.

• That being said, I received various requests from you guys about the R skills that you want to learn.
• and, as my personal opinion, I want you to use R to aid your research and jobs in the future.
• So, I will provide a bit more in depth knowledge of R in this course.

Objective of this course

The primary goals of this course is to provide you with the basic knowledge of R to conduct the following tasks:

Primary Goals

1. to create and manipulate the base-R object data
2. to do data manipulation with data.table package
3. to do data visualization with ggplot2 package
4. to conduct regression analysis with lm() and make a publish-ready regression table with modelsummary() package
5. to write Monte code for Carlo simulations using for loop function.

• I will also provide introduction to Rmarkdown and Quarto documents, to create a report with R codes and outputs.

• These tasks might be too easy for some students, so I will provide some additional advanced topics for those students.
• These are the plans for this course. Since we only have 5 days, the topics that I can hand with is very limited.
• I will Focusing on the R skills that would be useful for your Eocnometric class.

Rstudio

• What is it?
• Create New R code File
• Change the theme (Optional)
• Multiple panes (Optional)
• Command Palette (Optional)

• You can use app to write and run R codes, but it has a terrible graphic user interface.

• Rstudio is an another app build on top of R. It makes it much easier to edit R codes, see the results and organize the files.

• But still, you need R to run Rstudio! R is the engine of Rstudio.

• R studio looks like this:

Image Source: Rstudio User Guide

To create new R script file, click the + button on the top-left corner of the Rstudio, or hit Ctrl + Shift + N (Cmd + Shift + N on mac).

To save the file, click the floppy disk icon , or Ctrl + S (Cmd + S on macOS).

Image Source: Rstudio User Guide

You can change the appearance of Rstudio by going to Tools -> Global Options -> Appearance -> Editor theme and select your favorite theme.

Image Source: Rstudio User Guide

You can have multiple code panes in Rstudio. To create a new pane, go to Tools -> Global Options -> Pane Layout -> Add Column. In the same window, you can also change the layout of the panes.

In the following image, I have two source panes. Also, I changed the layout of the panes.

Recent R-studio has a new feature called “Command Palette.”. Hit Ctrl + Shift + P (Cmd + Shift + P on macOS) on your keyboard. (or go to Tools -> Show Command Palette).

From the command palette, you can do anything!

• create a new script file (R, Rmarkdown, Quarto etc.)
• open an R script file from your folder.
• open R project.
• open new session …. etc.

Source: Rstudio User Guide

Rstudio: Running Code

Let’s write some codes.

print("Hello, World!")

# This is a comment block.

R code

• Any thing you write in the source (or console) pane is regarded as R code.
• Mainly you use source pane to write the code.
• To run (execute) the code, select the code line, and click the “Run” bottom, or use the shortcut key: Ctrl + Enter (Cmd + Enter on macOS).

Comment block

R will not run the code line starting with #. It’s called comment block. You can use it to write a note for yourself or others.

Summary:

• Now you are familiar with Rstudio. As long as you know how to create and save R script, you are ready to go for the next lecture.

Note

• See this link. for more information about Rstudio.

• You don’t necessarily need to use R studio to use R (for example, you can use Visual Studio Code to run R), but, Rstudio is a great starting point to get familiar with R.