- Which of the following functions is used to read a CSV file into R?
- (A) read.csv()
- (B) csv.read()
- (C) load.csv()
- (D) read.table()
Answer: (A) read.csv()
2. What does the apply() function do in R?
- (A) Applies a function to a data frame or matrix margin (rows or columns)
- (B) Applies a function to all elements in a list
- (C) Applies a statistical test to the data
- (D) Applies a function to a specific subset of data based on conditions
Answer: (A) Applies a function to a data frame or matrix margin (rows or columns)
3. Which of the following functions can be used to create a linear model in R?
- (A) lm()
- (B) model()
- (C) lmfit()
- (D) linear.model()
Answer: (A) lm()
4. What is the purpose of the str() function in R?
- (A) Displays the structure of an R object
- (B) Converts a string into a factor variable
- (C) Creates a string from variables in a data frame
- (D) Converts an R object into a string
Answer: (A) Displays the structure of an R object
5. How do you handle missing values in a data frame in R?
- (A) Use the na.rm argument in functions like
sum(),mean() - (B) Use the
na.omit()function to remove missing values - (C) Use
complete.cases()to identify rows without missing values - (D) All of the above
Answer: (D) All of the above
6. In R, what does the ggplot2 package primarily provide?
- (A) Data manipulation functions
- (B) Statistical models and tests
- (C) A framework for creating data visualizations
- (D) A set of machine learning tools
Answer: (C) A framework for creating data visualizations
7. What is the primary purpose of the dplyr package in R?
- (A) To create and manipulate statistical models
- (B) To clean, filter, and summarize data efficiently
- (C) To create machine learning algorithms
- (D) To visualize data using various plotting techniques
Answer: (B) To clean, filter, and summarize data efficiently
8. Which function would you use to generate a random sample of size n from a normal distribution in R?
- (A) rnorm(n)
- (B) runif(n)
- (C) sample(n, size)
- (D) random.sample(n)
Answer: (A) rnorm(n)
9. What is the default method for computing the mean of a numeric vector in R?
- (A) mean()
- (B) median()
- (C) sum() / length()
- (D) avg()
Answer: (A) mean()
9. In R, which function is used to concatenate two or more vectors or strings?
- (A) concat()
- (B) c()
- (C) append()
- (D) combine()
Answer: (B) c()