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Question-1. What is R?
Answer-1: R is a programming language and environment used for statistical computing, data analysis, and visualization.
Question-2. Who developed R?
Answer-2: R was developed by Ross Ihaka and Robert Gentleman at the University of Auckland in 1993.
Question-3. What is the primary use of R?
Answer-3: R is primarily used for statistical analysis, machine learning, and data visualization.
Question-4. What are vectors in R?
Answer-4: Vectors are one-dimensional arrays that hold elements of the same data type.
Question-5. How do you create a vector in R?
Answer-5: Use the c() function. Example: c(1, 2, 3) creates a numeric vector.
Question-6. What is a data frame in R?
Answer-6: A data frame is a two-dimensional table-like structure where each column can have a different data type.
Question-7. How do you create a data frame in R?
Answer-7: Use the data.frame() function. Example: data.frame(Name=c("A", "B"), Age=c(25, 30)).
Question-8. What is the difference between a matrix and a data frame in R?
Answer-8: A matrix contains elements of the same data type; a data frame can hold different data types in each column.
Question-9. What is a list in R?
Answer-9: A list is a collection of objects in R that can contain elements of different data types.
Question-10. How do you create a list in R?
Answer-10: Use the list() function. Example: list(Name="A", Age=25, Score=95.5).
Question-11. What are factors in R?
Answer-11: Factors are used to represent categorical data with fixed levels.
Question-12. How do you create a factor in R?
Answer-12: Use the factor() function. Example: factor(c("Male", "Female", "Male")).
Question-13. What is the difference between apply() and sapply()?
Answer-13: apply() applies functions over rows/columns of a matrix; sapply() applies functions over lists/vectors and simplifies the output.
Question-14. What are packages in R?
Answer-14: Packages are collections of R functions, data, and documentation bundled together.
Question-15. How do you install a package in R?
Answer-15: Use the install.packages() function. Example: install.packages("ggplot2").
Question-16. How do you load a package in R?
Answer-16: Use the library() function. Example: library(ggplot2).
Question-17. What is the ggplot2 package in R?
Answer-17: ggplot2 is a popular package for creating complex and customizable visualizations.
Question-18. What are R's basic data types?
Answer-18: Basic data types include numeric, integer, character, logical, and complex.
Question-19. How do you check the structure of an object in R?
Answer-19: Use the str() function.
Question-20. What is the summary() function in R?
Answer-20: summary() provides a statistical summary of an object, like mean, median, and range.
Question-21. What is the use of the dim() function in R?
Answer-21: dim() retrieves or sets the dimensions of a matrix or data frame.
Question-22. What is R Markdown?
Answer-22: R Markdown is a tool for creating dynamic documents that combine code, output, and text.
Question-23. What is the plot() function in R?
Answer-23: plot() creates basic visualizations, like scatterplots and line graphs.
Question-24. What is the head() function in R?
Answer-24: head() displays the first few rows of a data frame or vector.
Question-25. What is the tail() function in R?
Answer-25: tail() displays the last few rows of a data frame or vector.
Question-26. What is the difference between mean() and median()?
Answer-26: mean() calculates the average of a dataset; median() calculates the middle value.
Question-27. What is the na.omit() function in R?
Answer-27: na.omit() removes rows with missing values (NA) from an object.
Question-28. How do you handle missing values in R?
Answer-28: Use functions like is.na(), na.omit(), or replace missing values using ifelse() or imputation.
Question-29. What is the use of the read.csv() function in R?
Answer-29: read.csv() reads data from a CSV file into a data frame.
Question-30. What is the write.csv() function in R?
Answer-30: write.csv() writes data from an R object to a CSV file.
Question-31. How do you create a sequence in R?
Answer-31: Use the seq() function. Example: seq(1, 10, by=2) creates a sequence from 1 to 10 in steps of 2.
Question-32. What is the difference between seq() and rep()?
Answer-32: seq() generates sequences; rep() repeats values.
Question-33. What is the dplyr package in R?
Answer-33: dplyr is a package for data manipulation, providing functions like filter(), select(), and mutate().
Question-34. What is the pipe operator (%>%) in R?
Answer-34: The pipe operator, used in dplyr, passes the output of one function as input to another.
Question-35. What is the difference between filter() and select() in dplyr?
Answer-35: filter() filters rows based on conditions; select() chooses specific columns.
Question-36. How do you combine datasets in R?
Answer-36: Use functions like merge() for data frames or cbind() and rbind() for matrices.
Question-37. What is a histogram in R?
Answer-37: A histogram visualizes the distribution of a numeric variable using bars.
Question-38. How do you create a histogram in R?
Answer-38: Use the hist() function. Example: hist(data$variable).
Question-39. What is a boxplot in R?
Answer-39: A boxplot shows the distribution, median, and outliers of a dataset.
Question-40. How do you create a boxplot in R?
Answer-40: Use the boxplot() function. Example: boxplot(data$variable).
Question-41. What is the use of the t.test() function in R?
Answer-41: t.test() performs a t-test to compare means between two groups.
Question-42. How do you write a function in R?
Answer-42: Use the function() keyword. Example: my_function <- function(x) { return(x^2) }.
Question-43. What is the lm() function in R?
Answer-43: lm() performs linear regression modeling.
Question-44. How do you test for correlation in R?
Answer-44: Use the cor() function to calculate the correlation coefficient.
Question-45. What is R's default working directory?
Answer-45: The default working directory is the current folder in which R is running.
Question-46. How do you change the working directory in R?
Answer-46: Use the setwd() function. Example: setwd("path/to/folder").
Question-47. How do you check the installed R version?
Answer-47: Use the version or R.version.string variable.
Question-48. What is R Shiny?
Answer-48: R Shiny is a package for building interactive web applications with R.
Question-49. What are control structures in R?
Answer-49: Control structures include if, else, for, while, and repeat for flow control.
Question-50. What is R's CRAN?
Answer-50: CRAN (Comprehensive R Archive Network) is the repository for R packages and source code.
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