MATH 315 Homework 03

Due 2025-09-19 by 11:59pm

  1. Create a dataset named donkeys with the following code
donkeys <- read.csv("https://raw.githubusercontent.com/roualdes/data/refs/heads/master/donkeys.csv")

  1. Read about the donkeys dataset from the online help file

  2. Pick a variable of your choice, or create one, and make a bar chart using ggplot2. Change the axis labels if you think it appropriate. Put a title on the plot.

  3. Pick a variable of your choice and make a histogram using ggplot2. Change the x-axis label being sure to include the correct units.

  4. Describe your histogram in at least two English sentences using new words from class.

  5. Pick two variables of your choice and make a scatter plot. Change the axis labels being sure to include the correct units.

  6. Describe your scatter plot in at least two English sentences using new words from class.

  7. Pick two variables of your choice and make a box plot (which should include more than one "box"). Change the appropriate axis label being sure to include the correct units.

  8. Describe your box plot in at least two English sentences using new words from class.

  9. Make a plot that includes one more variable than is standard for the plot type of your choice. For instance, if you choose to make a bar chart, then you should use two variables. If you choose to make a scatter plot, then you should use three variables.

If you finished Homework 03 early and want some extra practice problems that are worth 0 points. You do not need to do these, if you don't want.

  1. Instead of histograms, sometimes people prefer a smoothed histogram that doesn't require a choice of bins/bin width to be made. Such a smoothed histogram is a density plot and is created with the ggplot2 geometry geom_density(). Mimic your histogram from above. Specify the argument color, inside aes(...), to be equal to a categorical variable. Describe your density plot in at least two English sentences using new words from class.

  2. Recreate your scatter plot from above. Specify the argument color to color the points by a categorical variable of your choice. Add the geometry geom_smooth(method="lm", se = FALSE). To make your plot look better:

    • explore different plot themes
    • try specifying the argument alpha to the geom_point() geometry to be any decimal between 0 and 1
    • try following this tutorial to change the default color choices; pay attention to the name of the color palettes and the sub-section Customizing discrete data color/fill mappings: Using a colorbrewer scale.

    Describe your scatter plot in at least two English sentences using new words from class.