R Bootcamp Problem Set 6

Problem Set

Use the data files in the data/ directory to answer the questions.

For this problem set, you are allowed to help each other, but you are not allowed to post correct answers in slack.

The problem set is due 12pm on Sept 1.

Grading rubric

• Everything is good: full points
• Partially correct answer: depends on how many steps are correct
• Reasonable attempt: half points

Libraries

Load the libraries you need for analysis below.

Question 1 - 5 points

Run the following chunk:

set.seed(42)
x <- sample(1000, replace = TRUE)

Now use logical indexing to find the number of values > 450 in x.

Question 2 - 5 points

Count the number of species in the penguins tibble using forcats::fct_count()

Count number of island + sex combinations using dplyr::count(), and sort the result by count.

Question 3 - 5 points

Use stringr::str_c() to combine upper and lowercase letters from letters and LETTERS with a slash.

Your answer should look like: "A/a" "B/b" "C/c" etc.

Use stringr::str_split() or one of its variants to split up the strings you made above and extract the letter after the slash.

Question 4 - 5 points

Create a ggplot using the diamonds data set.

• Generate a ggridges::geom_density_ridges() for the prices, with a different fill color for each cut.
• Recolor the densities using ggplot2::scale_fill_brewer(), choosing a specific palette.
• make the outline of the densities black, and change their alpha to 0.2.
• change the theme to cowplot::theme_minimal_grid()
• remove the legend (google: “remove legend from ggplot2”)
• add an informative title and subtitle using ggplot2::labs().

Submit

Be sure to click the “Render” button to render the HTML output.

Then paste the URL of this Posit Cloud project into the problem set on Canvas.