1. What is the correct way to assign a value to a variable in R?
Answer:
Explanation:
In R, the most common way to assign a value to a variable is using the '<-' operator. The '=' operator can also be used, but '<-' is preferred in R programming for clarity and tradition.
2. Which of these is a valid variable name in R?
Answer:
Explanation:
Variable names in R can start with a period ('.') followed by a character, but they cannot start with a number, have dashes, or only consist of special characters.
3. How can you check the data type of a variable in R?
Answer:
Explanation:
In R, 'typeof()' is used to determine the data type of a variable, such as integer, double, character, etc.
4. Which of the following is not a basic data type in R?
Answer:
Explanation:
List is a data structure in R, not a basic data type. The basic data types include numeric, character, and integer.
5. How can you create a vector in R?
Answer:
Explanation:
In R, vectors are created using the 'c()' function, which combines values into a vector.
6. What will be the output of the following code? x <- "5"; as.numeric(x)
Answer:
Explanation:
The 'as.numeric()' function converts the character string "5" into the numeric value 5.
7. Which of the following is used to create a sequence of numbers in R?
Answer:
Explanation:
The 'seq()' function is used in R to create a sequence of numbers with specified start, end, and step values.
8. What will be the result of the expression 'is.na(NA)' in R?
Answer:
Explanation:
'is.na()' checks if a value is 'NA' (missing value) in R, and returns TRUE if it is.
9. How do you comment a single line in R script?
Answer:
Explanation:
In R, a single line comment is initiated with the '#' symbol.
10. Which function is used to install packages in R?
Answer:
Explanation:
The 'install.packages()' function is used to install new packages in R, while 'library()' or 'require()' are used to load them into the current session.
11. What does the R function 'rm()' do?
Answer:
Explanation:
The 'rm()' function is used to remove specified objects from the memory (workspace) in R.
12. Which of these is the correct way to access the third element of a vector 'vec' in R?
Answer:
Explanation:
In R, elements of a vector are accessed using square brackets, with the index of the element inside the brackets.
13. How is a missing value represented in R?
Answer:
Explanation:
In R, 'NA' is used to represent missing or unavailable data.
14. Which function can be used to read a CSV file in R?
Answer:
Explanation:
The 'read.csv()' function is widely used for reading CSV (Comma Separated Values) files into R.
15. What is the outcome of the expression 'sqrt(-1)' in R?
Answer:
Explanation:
In R, taking the square root of a negative number results in 'NaN', which stands for 'Not a Number'.