ANLY 512 Problem Set #4 - More ggplot2

More Visualization Processes

Directions

The objective of this assignment is to complete and explain basic plots before moving on to more complicated ways to graph data.

• To ensure accuracy pay close attention to axes and labels, you will be evaluated based on the accuracy and expository nature of your graphics. Make sure your axis labels are easy to understand and are comprised of full words with units if necessary.

Each question is worth 5 points.

To submit this homework you will create the document in Rstudio, using the knitr package (button included in Rstudio) and then submit the document to your Rpubs account. Once uploaded you will submit the link to that document on Canvas. Please make sure that this link is hyperlinked and that I can see the visualization and the code required to create it (echo=TRUE).

Questions

1. The following questions use the Marriage data set from the mosaicData package.

• Create an informative and meaningful data graphic.
• Identify each of the visual cues that you are using, and describe how they are related to each variable.

My plot uses the visual cue of length to represent the average Age of marriage separated by Bride and Groom. On average, the Grooms are 3 years older than the Bride.

The coordinate system is Cartesian. Context is provided by the title and axis labels.

• Create a data graphic with at least five variables (either quantitative or categorical). For the purposes of this exercise, do not worry about making your visualization meaningful—just try to encode five variables into one plot.

Marriage %>% 
  group_by(person) %>% 
  summarize(avg_age = round(mean(age), 0)) %>% 
  ggplot(aes(x = person, y = avg_age)) +
  theme_classic() +
  geom_bar(stat = "identity") +
  geom_text(aes(label = avg_age), vjust = -0.3, size = 4) +
  scale_y_continuous(expand = c(0,0),
                     limits = c(0,38)) + 
  # Change the appearance of axis tick labels
  theme(axis.text.x = element_text(face="bold", size=14)) +
  labs(x = NULL, y = "Average Marriage Age",
       title = "What Is the Average Age of Marriage in Mobile County, Alabama?")

ggplot(data = Marriage, aes(x=age, y=college, color = person, shape = race, size = hs)) + 
  geom_point() +
  theme_classic() +
  labs(x = "Age", y = "Years in College",
       title = "The Relationship between Age of Marriage and Years in College by Race, Title, and Years in High School")

Your objective for the next four questions will be write the code necessary to exactly recreate the provided graphics.

2. Boxplot Visualization

This boxplot was built using the mpg dataset. Notice the changes in axis labels.

ggplot(mpg, aes(manufacturer, hwy)) +
  geom_boxplot() + 
  coord_flip() + 
  labs(x="Vehicle Manufacturer", y="Highway Fuel Efficiency (miles/gallon)") + 
  theme_classic()

3. Stacked Density Plot

This graphic is built with the diamonds dataset in the ggplot2 package.

ggplot(diamonds, aes(price,fill=cut,color=cut)) + 
  geom_density(alpha=0.3, size=0.3) +
  scale_fill_discrete_qualitative(palette = "Dark 3") + 
  labs(x="Diamond Price (USD)", y="Density", title="Diamond Price Density")

4. Sideways bar plot

This graphic uses the penguins dataset and shows the counts between males and females by species.

ggplot(penguins, aes(x = sex, fill = species)) +
  geom_bar(alpha = 0.8) +
  scale_fill_manual(values = c("darkorange","purple","cyan4"), 
                    guide = FALSE) + #makes legend go away
  theme_minimal() +
  facet_wrap(~species, ncol = 1) +
  coord_flip() +
  labs(y="Count", x="Sex")

5. Scatterplot

This figure examines the relationship between bill length and depth in the penguins dataset.

ggplot(data = penguins, aes(x = bill_length_mm, y = bill_depth_mm)) +
  geom_point(aes(color = species, 
                 shape = species),
             size = 2)  +
  guides(shape = 'none') + #remove extra legends
  geom_smooth(method = "lm", se = FALSE, aes(color = species)) +
  scale_color_manual(values = c("darkorange","darkorchid","cyan4"))  +
  labs(
    color = 'Species', #legend label
    x = 'Bill Length (mm)',
    y = 'Bill Depth (mm)')