#1 R Programming Language Test - 74+ MCQs: R Programming Language test: Assess Your Proficiency with R Questions and Answers

1. What is the purpose of the 'mean()' function in R?

Calculating Median

Calculating Mode

Calculating Mean

Calculating Standard Deviation

2. What does the 'tapply()' function in R do?

Applies a transformation to a matrix

Transposes a data frame

Applies a function to each group of a vector

Transforms a table structure

3. How can you read a CSV file into a data frame in R?

read.csv('file.csv')

load.csv('file.csv')

import.csv('file.csv')

read.data.frame('file.csv')

4. How can you create a named list in R with elements 'a' and 'b'?

list(a, b)

create_list(a, b)

named_list(a, b)

generate_list(a, b)

5. What is the purpose of the 'lm()' function in R?

Linear Model Fitting

Logical Matrix Computation

List Manipulation

Loop Management

6. How can you check if a variable 'x' is numeric in R?

is_numeric(x)

check_numeric(x)

numeric(x)

is.numeric(x)

7. What does the 'summary()' function provide for a data frame in R?

Detailed Statistics

Data Frame Structure

Data Frame Summary

Data Frame Visualization

8. In R, how can you extract a specific column from a data frame?

selectColumn(dataFrame, columnName)

dataFrame.columnName

extractColumn(dataFrame, columnName)

dataFrame[, columnName]

9. In R, explain the difference between '<<-' and '->>' assignment operators.

'<<-' assigns a value to a variable in the global environment, while '->>' assigns in the reverse direction.

'<<-' is used for bitwise left shift, while '->>' is used for bitwise right shift.

'<<-' is a shortcut for assigning to a variable in a function, while '->>' is used for global variable assignment.

'<<-' is a deprecated operator, and '->>' is the recommended assignment operator in R.

10. In R, what is the purpose of the 'ifelse()' function?

To create a loop

To check if a condition is TRUE or FALSE

To import external data

To define a custom function

R Programming Language MCQ Test 5