How does R handle data frames that contain columns of different data types?

  • It automatically converts all columns to the same data type
  • It assigns a common data type to all columns
  • It treats each column independently with its own data type
  • It raises an error
R treats each column in a data frame independently, allowing columns to have different data types. This means that each column can be operated on and analyzed separately based on its specific data type.

Suppose you're asked to write a function in R that takes a vector of numbers and applies a mathematical operation (like squaring or taking the square root) to each number. The mathematical operation itself should also be a function, nested within your main function. How would you do it?

  • function_name <- function(numbers, operation) { result <- sapply(numbers, operation); return(result) }
  • function_name <- function(numbers, operation) { result <- lapply(numbers, operation); return(result) }
  • function_name <- function(numbers, operation) { result <- vapply(numbers, operation, FUN.VALUE = numeric(1)); return(result) }
  • All of the above
To write a function in R that takes a vector of numbers and applies a mathematical operation (like squaring or taking the square root) to each number, with the mathematical operation itself nested within the main function, you can use the following code: function_name <- function(numbers, operation) { result <- sapply(numbers, operation); return(result) }. The sapply() function is used to apply the operation function to each element in the numbers vector, and the result is returned.

Imagine you're working with a data set in R that contains missing values. How would you handle the missing values in your statistical analysis?

  • Exclude the observations with missing values from the analysis
  • Use imputation techniques to fill in the missing values
  • Analyze the available data and report the limitations due to missing values
  • All of the above
When working with a data set in R that contains missing values, handling them in your statistical analysis depends on the nature and extent of missingness. You may choose to exclude the observations with missing values from the analysis, use imputation techniques to fill in the missing values based on certain assumptions, or perform the analysis on the available data and report the limitations or potential bias introduced by the missing values. The choice of approach should be guided by the research question, the amount of missingness, and the assumptions underlying the analysis.

How do you implement a recursive function in R?

  • Define the base case and the recursive case within the function
  • Use the loop keyword to initiate recursion
  • Use the recurse function to call the function recursively
  • All of the above
To implement a recursive function in R, you define the base case and the recursive case within the function. The base case specifies a condition that determines when the recursion should stop, while the recursive case defines how the function calls itself with modified arguments to approach the base case. This iterative process continues until the base case is reached.

Can you discuss how operations on data frames work in R and how they differ from operations on matrices or arrays?

  • Operations on data frames are column-wise
  • Operations on data frames are element-wise
  • Operations on data frames are row-wise
  • Operations on data frames are matrix operations
Operations on data frames in R are typically performed column-wise, meaning that functions and operations are applied to each column separately. This is different from matrices or arrays where operations are typically element-wise or based on matrix algebra rules.

How would you handle a situation where you need to calculate the correlation between two vectors in R?

  • Use the cor() function
  • Use the corr() function
  • Use the correlation() function
  • Use the relation() function
In R, we use the cor() function to calculate the correlation between two vectors. For example, if x and y are vectors, cor(x, y) would return the correlation between x and y.

To change the color of segments in a pie chart in R, you would use the ______ parameter.

  • col
  • labels
  • fill
  • colors
To change the color of segments in a pie chart in R, you would use the fill parameter. By providing a vector of colors corresponding to each segment, you can assign different colors to different segments in the pie chart.

Imagine you're debugging a piece of R code that uses nested functions and encountering unexpected behavior. What are some strategies you could use to identify the problem?

  • Use print statements or the browser() function to inspect intermediate results
  • Step through the code using a debugger
  • Check the input data and ensure it meets the expected format
  • All of the above
When debugging a piece of R code that uses nested functions and encountering unexpected behavior, you can use strategies such as using print statements or the browser() function to inspect intermediate results, stepping through the code using a debugger, and checking the input data to ensure it meets the expected format. These strategies help in identifying potential issues or discrepancies in the code and allow for thorough debugging and troubleshooting.

If a vector in R is created with elements of different data types, R will coerce the elements to the most flexible type, which is ______.

  • character
  • numeric
  • logical
  • integer
If a vector in R is created with elements of different data types, R will coerce the elements to the most flexible type, which is the character data type. The character type is considered the most flexible because it can represent other types by converting them to strings.

To fit a linear regression model in R, you would use the ______ function.

  • lm()
  • regmodel()
  • linreg()
  • regression()
To fit a linear regression model in R, you would use the lm() function. The lm() function stands for "linear model" and is used for estimating the coefficients of a linear regression model based on the given data.