Lecture 1: Introduction to R

Question 1

What is R?

Answer 1

A free statistical programming language developed by two New Zealanders.

Question 2

What does R enable us to do?

Answer 2

• Do calculations that are basic/complex
• Undertake statistical analyses of data
• Construct graphs from data
• Write programs to carry out statistical analyses
• Keep records of everything you do in an analysis

Question 3

Why use R (instead of SPSS)?

Answer 3

• It is open source
• Extremely powerful
• Comprehensive
• Commonly used tool
• Easy

Question 4

What are the basic numerical operators?

Answer 4

^ = power
* = multiplication
/ = division
\+ = summation
- = subtraction

Question 5

What are the logical operators?

Answer 5

& = and
| = or
! = not

Question 6

What are R functions?

Answer 6

Functions undertake calculations, and require a set of parentheses after their name and the arguments listed within them.

Question 7

What are variables?

Answer 7

They provide a way of labelling and storing information, and correspond to computer memory that is allocated to each bit of information.

Question 8

What are the requirements for variable names?

Answer 8

• Starts with a letter
• Letters, periods, and numbers can be used
• An underscore can be used but should be avoided
• Cannot contain a space or other characters
• Cannot be a reserved word or function e.g TRUE

Question 9

Advantages of variables?

Answer 9

• They can store multiple values

- Can be combined into data frames

Question 10

What is a variable that contains one or more values called?

Answer 10

An atomic vector.

Question 11

Which function creates vectors?

Answer 11

c()

Question 12

What are the ways we can identify elements within a vector?

Answer 12

• Position number e.g boredom [1]

- Name e.g “boredom”

Question 13

How can we select elements?

Answer 13

• Position number e.g boredom[-2] or boredom c(1,3)
• Logical values e.g boredom [c(TRUE, TRUE, FALSE)]
• Logical expressions e.g boredom[boredom

Question 14

What are packages?

Answer 14

User-written collections of functions, data, and help documents that can be used in data analysis.

Question 15

What is installing and loading a package?

Answer 15

Install: The package is in your computer
Load: The package is made available in R studio

Question 16

What are the types of variables?

Answer 16

• Factor variables (nominal categorical variables)

- Numeric variables (continuous variables)

Question 17

What is an R script file?

Answer 17

A text file that contains all the commands required to undertake the analysis

Question 18

How do you run a script file?

Answer 18

By using the source function.

Question 19

What are simple functions of R?

Answer 19

• sqrt() = square root
• round() = round a number
• log() = logarithm
• exp() = exponentiation
• abs() = absolute value

Question 20

What are the variable classes?

Answer 20

• Numeric e.g 212
• Logical e.g TRUE
• Character e.g “a cat”

Question 21

How do you assign a variable>