R Basics - Day 1

Question 1

What is R?

Answer 1

A programming language used for statistical analysis, data manipulation, and visualization.

Question 2

What is RStudio?

Answer 2

An Integrated Development Environment (IDE) for writing, running, and debugging R code.

Question 3

How do you assign a value to a variable in R?

Answer 3

Using the ‹- operator.
(e.g., x ‹- 10)

Question 4

What is a vector in R?

Answer 4

A sequence of elements of the same type.
[e.g., c (1, 2, 3) ]

Question 5

How do you create a vector in R?

Answer 5

Use the c () function.
example: numbers <- c(10, 20, 30)

Question 6

What function calculates the mean of a vector?

Answer 6

mean ()
example: mean (numbers)

Question 7

How do you access an element in a vector?

Answer 7

Use square brackets.
example: numbers[1] gives the first element

Question 8

How do you calculate the sum of a vector?

Answer 8

Use the sum () function.
example: sum (numbers)

Question 9

What is a data frame in R?

Answer 9

A table-like structure with rows and columns, where each column can be a different data type.

Question 10

How do you create a data frame in R?

Answer 10

Use the data. frame() function.

example:

names <- c(“Alice”, “Bob”)
scores <- c(85, 90)
df <- data.frame(Name = names, Score = scores)

Question 11

How do you view the first rows of a data frame?

Answer 11

Use the head () function.
example: head (df)

Question 12

What does the print () function do in R?

Answer 12

Outputs the value of a variable or expression to the console.

Question 13

What does the class () function do in R?

Answer 13

Returns the data type of a variable.
example: class (numbers)

Question 14

What does the length () function do?

Answer 14

Returns the number of elements in a vector.
example: length (numbers)

Question 15

What is the purpose of the help () function?

Answer 15

Displays documentation for a function. example: help (mean)

Question 16

What is a logical operator in R?

Answer 16

An operator that returns TRUE or
FALSE.
examples: <, >, ==, !=

Question 17

How do you check if all elements in a vector are greater than a value?

Answer 17

Use all ().
example: all (numbers > 5)

Question 18

How do you check if any element in a vector meets a condition?

Answer 18

Use any ().
example: any (numbers > 25)

Question 19

How do you install a package in R?

Answer 19

Use install.packages(“package_name”)

Question 20

How do you load a package in R?

Answer 20

Use library(package_name)