4  Recommended exercises

These are the recommended exercises in R4DS with some comments. We recommend reading through these recommendations before starting the exercises as they are meant to help you learn more efficiently. Some of the exercises in the book are rather straight forward, but some are more difficult (as we also struggled with them when writing the solutions). So if you feel that you don’t know where to start with an exercise or that you are stuck, consult the suggested solutions.

Data visualization

All exercises.

  • 1.2.4 Exercise 4: try using geom_density as well and try using geom_density and coloring by cut.

Data transformation

3.2 Rows

All exercises

Read 3.3 first and use the following functions: * relocate or select to move columns of interest to the front of the tibble, otherwise it is hard to see the result. * Use mutate in Exercise 3 to create a new variable for speed and use that variable for sorting, i.e. arrange-ing. If you are having trouble figuring out the mathematical expression, remember from high school physics the relationship between time, distance, and speed. In Swedish “SVT”-triangeln. If you just want the answer, look at 3.3.1.

3.3 Columns

All exercises

  • In exercise 1, try to think about the relationship. It is not necessary to successfully create a new variable that is the same as dep_delay. See solutions for a suggestion of how, even though it may be beyond the scope of the course.
  • In exercise 4 for, use ?any_of and look at the function from the tidyselect package.

3.5 Groups

All exercises in 3.5

  • In exercise 1, remember to use na.rm when calculating the average.

Exploratory data analysis

Try to do all exercises but some are quite difficult. If you get stuck consult the suggested solutions.

The exercises requires some basic knowledge about diamonds: Measurements

  • x, y, z: The dimensions of a diamond (width, length, height)

The four Cs of diamond grading * Carat: A unit of mass (like grams) * Cut: Style or design, but rather symmetry, proportioning, and polishing than shape. A well cut diamond is more *luminous*. * Clarity: The existence and visual appearance of internal characteristics, called inclusions, and surface defects, called blemishes. * Color: A perfect diamond has no hue or color.

Communication

No recommended exercises, instead practice plotting as you work with chapter 10 and assignments.