Exploratory Analysis

Data visualization, part 1. Code for Quiz 7..

Load the R package we will use.
```
library(tidyverse)
```

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 file correspond with your quiz answers -After you check all your code chunks run then you can knit it. It won’t knit until the ??? are replaced -The quiz assumes you have watched the videos had worked through the exercises in exercises_slides-1-49.Rmd
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

-reate 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 purple to all the points

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

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

-See how shapes and sizes of points can be specified here: https://ggplot2.tidyverse.org/articles/ggplot2-specs.html#sec:shape-spec -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 plus -set the point size to 1 -set the point transparency 0.4

ggplot(faithful) + 
   geom_point(aes(x = eruptions, y = waiting), 
   shape = "plus", size = 1, alpha =0.4)

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-side-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-side-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 purple3 -make the shape of the dot square -make the dot size 8

ggplot(mpg) + 
  geom_jitter(aes(x = class, y = hwy), width = 0.2) +
  stat_summary(aes(x = class, y = hwy), geom = "point", 
  fun = "median", color = "purple3", 
  shape = "square", size = 8 )

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