Getting Started with R Programming

15 questions

1. 1. What is the correct way to set a working directory in R?
   `setwd("C:/r-programming/data")``setwd("C:\r-programming\data")``setwd(C:/r-programming/data)``setwd[C:/r-programming/data]`
2. 2. Which operator is most commonly used for variable assignment in R?
   `<-``=``->``:=`
3. 3. What will be the output of this code?
   `"numeric"``"integer"``"vector"``"array"`
4. 4. How do you convert a numeric value to an integer in R?
   `as.integer(8)``to.integer(8)``integer(8)``int(8)`
5. 5. What is the correct way to access the third element of a vector named 'earnings'?
   `earnings[3]``earnings(3)``earnings{3}``earnings[3rd]`
6. 6. How would you create a 3x2 matrix from the vector c(64,31,65,28,66,35) filled by row?
   `matrix(c(64,31,65,28,66,35), nrow=3, byrow=TRUE)``matrix(c(64,31,65,28,66,35), ncol=2)``matrix(c(64,31,65,28,66,35), 3, 2)``array(c(64,31,65,28,66,35), dim=c(3,2))`
7. 7. What will this code return?
   `"logical"``"boolean"``"numeric"``"character"`
8. 8. How do you create an ordered factor in R with levels "small", "medium", "large"?
   `factor(x, ordered=TRUE, levels=c("small", "medium", "large"))``ordered.factor(x, levels=c("small", "medium", "large"))``factor(x, sort=TRUE)``as.ordered(x)`
9. 9. What is the correct way to add row names to a matrix?
   `rownames(matrix) <- c("Mon", "Tue", "Wed")``names(matrix) <- c("Mon", "Tue", "Wed")``row.names(matrix) = c("Mon", "Tue", "Wed")``matrix$rownames <- c("Mon", "Tue", "Wed")`
10. 10. What function would you use to calculate the sum of all elements in a vector?
    `sum(vector)``total(vector)``vector.sum()``colSum(vector)`
11. 11. How do you add a comment in R code?
    `# This is a comment``// This is a comment``/* This is a comment */``-- This is a comment`
12. 12. Which of these is the correct way to concatenate strings in R?
    `paste("Hello", "World")``"Hello" + "World"``concat("Hello", "World")``join("Hello", "World")`
13. 13. What will be the output of this code?
    `TRUE``FALSE``1``Error`
14. 14. How do you check which objects are currently in your R workspace?
    `ls()``objects()``list()``workspace()`
15. 15. What does the following code do?
    Returns "GOOG"Returns "stock"Returns "Google"Returns an error