Edit the code chunks below and knit the document to check if the answers are correct. Make sure you don’t change the names of the variables that are given to you, or the answer checks won’t work.

Question 1

Create a variable called my_pals containing the names of three of your friends. This should be a three-element vector of type character.

my_pals <- c("Alvin", "Simon", "Theodore")

Question 2

The chunk below creates an integer vector ages with the ages of five people. (Note: defining a number with the sufficx L, e.g., 26L, defines 26 as type integer rather than type double.) Calculate how old they will be in ten years using a vectorized operation and store the result in the variable ages_10.

ages <- c(26L, 13L, 47L, 62L, 18L)

ages_10 <- ages + 10

Question 3

The code below has an error and won’t run. Fix the code.

# alternatively, you could load the library first: library(fortunes)

my_fortune <- fortunes::fortune()

## Basically R is reluctant to let you shoot yourself in the foot unless you
## are really determined to do so.
##    -- Bill Venables (about the warning hist() issues when being called
##       with unequal interval widths and freq=TRUE)
##       R-help (May 2008)

Question 4

Call the rnorm() function to generate 10 random values from a normal distribution with a mean of 800 and a standard deviation of 20, and store the result in the variable random_vals.

random_vals <- rnorm(10, 800, 20)

Question 5

Use the help function to figure out what argument you need to set to ignore NA values when calculating the mean of the_values. Change the function below to store the mean of the_values in the variable the_mean.

the_values <- c(1,1,1,2,3,4,6,8,9,9, NA) # do not alter this line
the_mean <- mean(the_values, na.rm = TRUE)

Answer Checks

You’ve made it to the end. Make sure you are able to knit this document to HTML. You can check your answers below in the knit document.

Question Answer
Question 1 correct
Question 2 correct
Question 3 correct
Question 4 correct
Question 5 correct