Exploratory analysis

Data visualization, part 1. Code for Quiz 7.

  1. Load the ‘R’ Packages that we will use
library(tidyverse)
  1. Quiz questions

-Replace all the ???s. These are answers on your moodle quiz.

Run all the individual code chunks to make sure the answers in this correspond with your quiz questions

After you check all your code chunks run then you can knit it. It won’t knit until all ??? are replaced

The quiz assumes you have watched the videos had worked through the exercises in exercise_slides-1-49.Rmd

  1. Pick one of your plots to save as your preview plot. Use the ggsave command at the end of the chunk of the plot that you want to preview.

Question: modify slide 34

Create a plot with the faithful dataset

add points with geom_point

assign the variable eruptions to the x-axis

assign the variable waiting to the y-axis

-color the points according to whether waiting is smaller or greater than 64

ggplot(faithful) + 
   geom_point(aes(x = eruptions, y = waiting, 
                  colour = waiting > 64))

Question: modify intro-slide 35

Create a plot with the faithful dataset

add points with geom_point

assign the variable eruptions to the x-axis

assign the variable waiting to the y-axis

assign the color dodgerblue to all the points

ggplot(faithful) + 
   geom_point(aes(x = eruptions, y = waiting),
              colour = "dodgerblue")

Question: modify intro-slide 36

Create a plot with the faithful dataset

use geom_histogram() to plot the distribution of waiting time

assign the variable waiting to the x-axis

ggplot(faithful) + 
   geom_histogram(aes(x = waiting))

Question: modify geom-ex-1

Create a plot with the faithful dataset

add points with geom_point

assign the variable eruptions to the x-axis

assign the variable waiting to the y-axis

set the shape of the points to square

set the point size to 5

set the point transparency 0.5

ggplot(faithful) + 
   geom_point(aes(x = eruptions, y = waiting), 
   shape = "square", size = 5, alpha =0.5)

Question: modify geom-ex-2

Create a plot with the faithful dataset

use geom_histogram() to plot the distribution of the eruptions (time)

fill in the histogram based on whether eruptions are greater than or less than 3.2 minutes

ggplot(faithful) + 
   geom_histogram(aes(x = eruptions, fill = eruptions > 3.2 ))

Question: modify stat-slide-40

Create a plot with the mpg dataset

add geom_bar() to create a bar chart of the variable manufacturer

ggplot(mpg) + 
   geom_bar(aes(x = manufacturer))

Question: modify stat-slide-41

change code to count and to plot the variable manufacturer instead of class

mpg_counted <- mpg %>% 
  count(manufacturer, name = 'count')
ggplot(mpg_counted) + 
  geom_bar(aes(x = manufacturer, y = count), stat = 'identity')

Question: modify stat-slide-43

change code to plot bar chart of each manufacturer as a percent of total

change class to manufacturer

ggplot(mpg) + 
  geom_bar(aes(x = manufacturer, y = after_stat(100 * count / sum(count))))

Question: modify answer to stat-ex-2

for reference see: https://ggplot2.tidyverse.org/reference/stat_summary.html?q=stat%20_%20summary#examples

Use stat_summary() to add a dot at the median of each group

color the dot purple

make the shape of the dot plus

make the dot size 3

ggplot(mpg) + 
  geom_jitter(aes(x = class, y = hwy), width = 0.2) +
  stat_summary(aes(x = class, y = hwy), geom = "point", 
  fun = "median", color = "purple", 
  shape = "plus", size = 3)


ggsave(filename = "preview.png", 
       path = here::here("_posts", "2021-03-30-exploratory-analysis"))