R Programming Langauge Practice Quiz: R Quiz 1

1. You are experiencing slow performance when working with large datasets in R. Which package offers functions for data manipulation and optimization to improve performance?

• dplyr
• tidyr
• readr
• ggplot2

2. When using the %in% operator in R, what is its primary use?

• Logical OR operation
• Element-wise multiplication
• String concatenation
• Set membership test

3. Your R script generates the error message "Error in if (condition) {: missing value where TRUE/FALSE needed." What does this error typically indicate?

• A syntax error in the 'if' statement
• An attempt to perform an operation on missing or NA values
• An issue with the 'if' condition, which is not evaluating to TRUE or FALSE
• A missing parenthesis in the 'if' statement

4. When working with dates and times in R, which package provides functions for parsing, formatting, and working with date-time objects?

• gettime
• thisisdate
• reshape2
• lubridate

5. When running your R script, you get the error message "object of type 'closure' is not subsettable." What could be the cause of this error?

• Attempting to access an element of a non-indexed object
• Trying to index a function that is not allowed
• Using a variable that is not defined within the current scope
• Incorrect usage of the $ operator on a function

6. You are working with categorical data in R and need to create dummy variables for regression analysis. What function can you use to convert categorical data into dummy variables?

• encode_categorical()
• as.dummies()
• model.matrix()
• dummy_data()

7. Your R script contains non-ASCII characters in comments, and you encounter encoding issues. Which encoding declaration can you include at the beginning of your script to address this?

• #encoding: latin1
• #encoding: ascii
• # -*- encoding: utf-8 -*-
• #encoding: UTF-16

8. You want to conduct hypothesis testing for two independent groups in R. What function should you use for a non-parametric test, suitable for non-normally distributed data?

• wilcox.test()
• chisq.test()
• t.test()
• cor.test()

9. Your R script generates an error message that reads "subscript out of bounds" when attempting to access elements in a data structure. What is a common reason for this error?

• Attempting to access an element that doesn't exist
• Incorrect usage of the [[]] operator for subsetting
• Using too many nested loops in the code
• The data structure is not properly defined.

10. When working with strings in R, you encounter the error message "argument 'pattern' has length > 1 and only the first element will be used." What does this error suggest?

• A bug in the R interpreter
• Using the strsplit() function incorrectly
• Attempting to apply a regular expression with multiple patterns
• Incorrect usage of the grep() function