Data Visualization 1Bora Jin1 / 14

Material

🎥 Watch Data and Visualization

Slides

🎥 Watch Visualizing Data with ggplot2

Slides

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Today's Goal

Build up an effective visualization systematically layer by layer with ggplot2

"The simple graph has brought more information to the data analyst's mind than any other device" - John Tukey

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Quiz

Q - What does each row of a dataset represent?

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Quiz

Q - What does each row of a dataset represent?

Observation

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Quiz

Q - What does each row of a dataset represent?

Observation

Q - What does each column of a dataset represent?

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Quiz

Q - What does each row of a dataset represent?

Observation

Q - What does each column of a dataset represent?

Variable

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Quiz

Q - What does each row of a dataset represent?

Observation

Q - What does each column of a dataset represent?

Variable

Q - All variables in a dataset must be in the same type (character, integer, etc.). (T/F)

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Quiz

Q - What does each row of a dataset represent?

Observation

Q - What does each column of a dataset represent?

Variable

Q - All variables in a dataset must be in the same type (character, integer, etc.). (T/F)

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Quiz

Q - What does each row of a dataset represent?

Observation

Q - What does each column of a dataset represent?

Variable

Q - All variables in a dataset must be in the same type (character, integer, etc.). (T/F)

Q - In this class, we mainly focus on variables having a single entry per observation. (T/F)

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Quiz

Q - What does each row of a dataset represent?

Observation

Q - What does each column of a dataset represent?

Variable

Q - All variables in a dataset must be in the same type (character, integer, etc.). (T/F)

Q - In this class, we mainly focus on variables having a single entry per observation. (T/F)

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Quiz

Q - Which function spits out the dimension of a dataset?

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Quiz

Q - Which function spits out the dimension of a dataset?

dim() (row, column)

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Quiz

Q - Which function spits out the dimension of a dataset?

dim() (row, column)

Q - How to check the number of rows of a dataset?

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Quiz

Q - Which function spits out the dimension of a dataset?

dim() (row, column)

Q - How to check the number of rows of a dataset?

nrow()

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Quiz

Q - Which function spits out the dimension of a dataset?

dim() (row, column)

Q - How to check the number of rows of a dataset?

nrow()

Q - How to check the number of columns of a dataset?

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Quiz

Q - Which function spits out the dimension of a dataset?

dim() (row, column)

Q - How to check the number of rows of a dataset?

nrow()

Q - How to check the number of columns of a dataset?

ncol()

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Quiz

Q - What is the information that you cannot get using glimpse()?

a. number of rows

b. number of cols

c. list of variables

d. variable types

e. summaries of variables

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Quiz

Q - What is the information that you cannot get using glimpse()?

a. number of rows

b. number of cols

c. list of variables

d. variable types

e. summaries of variables

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Quiz

Q - What is EDA?

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Quiz

Q - What is EDA?

Approach to analysing datasets to summarize and describe its main characteristics
Often visual

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Quiz

Q - What is EDA?

Approach to analysing datasets to summarize and describe its main characteristics
Often visual

Q - Why is visualization important?

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Quiz

Q - What is EDA?

Approach to analysing datasets to summarize and describe its main characteristics
Often visual

Q - Why is visualization important?

It can reveal a new story that summary statistics could miss!

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Quiz

Q - What is EDA?

Approach to analysing datasets to summarize and describe its main characteristics
Often visual

Q - Why is visualization important?

It can reveal a new story that summary statistics could miss!

Q - Before plotting, what package do we load?

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Quiz

Q - What is EDA?

Approach to analysing datasets to summarize and describe its main characteristics
Often visual

Q - Why is visualization important?

It can reveal a new story that summary statistics could miss!

Q - Before plotting, what package do we load?

library(tidyverse) (ggplot2 $\in$ tidyverse)

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Quiz

Q - When plotting, what are the three fundamental things to define and the relevant code?

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Quiz

Q - When plotting, what are the three fundamental things to define and the relevant code?

Data in ggplot(data = )
Aesthetics in ggplot(mapping = aes())
Geometries in geom_xxxx()

layers added by +

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Quiz

Q - When plotting, what are the three fundamental things to define and the relevant code?

Data in ggplot(data = )
Aesthetics in ggplot(mapping = aes())
Geometries in geom_xxxx()

layers added by +

ggplot(data = [dataset], 
       mapping = aes(x = [x-variable], y = [y-variable])) +
   geom_xxx() +
   other options

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Quiz

Q - What are other options include?

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Quiz

Q - What are other options include?

Labels and legends in labs()
More aesthetics options (color, shape, size, alpha)
Faceting
Many more!

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Quiz

Q - What are other options include?

Labels and legends in labs()
More aesthetics options (color, shape, size, alpha)
Faceting
Many more!

Q - For aesthetics options, can you explain mapping vs. setting?

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Quiz

Q - What are other options include?

Labels and legends in labs()
More aesthetics options (color, shape, size, alpha)
Faceting
Many more!

Q - For aesthetics options, can you explain mapping vs. setting?

Mapping: map plotting characters to a specific variable in data through aes()
Setting: determine them without regard to data values through geom_xxxx()

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Quiz

Q - Why faceting?

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Quiz

Q - Why faceting?

To explore conditional relationships
Multiple smaller plots in one plot

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Quiz

Q - Why faceting?

To explore conditional relationships
Multiple smaller plots in one plot

Q - Two functions for faceting?

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Quiz

Q - Why faceting?

To explore conditional relationships
Multiple smaller plots in one plot

Q - Two functions for faceting?

facet_grid([row-variable] ~ [column-variable])
facet_wrap(~ [variable])

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Questions?

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Let's Practice Together!

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Data Visualization 1

Bora Jin

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