Scatter Plot

## Introduction

### Agenda

• build scatter plots
• modify point
• color
• fill
• alpha
• shape
• size
• fit regression line

## Plot

### Example

ggplot(mtcars) +
geom_point(aes(disp, mpg))

### Instruction

• map x to disp
• map y to mpg
# scatter plot of disp and mpg
ggplot(mtcars) +
geom_point(aes(disp, mpg))

## Aesthetics

### Introduction

Now let us modify the aesthetics of the points. There are two ways:

• map them to variables using the aes() function
• specify values

## Color

### Example

ggplot(mtcars) +
geom_point(aes(disp, mpg, color = factor(cyl)))

### Instructions

• map color to cyl
# map color to cyl
ggplot(mtcars) +
geom_point(aes(disp, mpg, _____)

### Example

ggplot(mtcars) +
geom_point(aes(disp, mpg, color = hp))

### Instructions

• map color to hp
# map color to cyl
ggplot(mtcars) +
geom_point(aes(disp, mpg, _____)

### Example

ggplot(mtcars) +
geom_point(aes(disp, mpg), color = 'blue')

### Instructions

• set color to 'blue'
# set color to 'blue'
ggplot(mtcars) +
geom_point(aes(disp, mpg), _____)

### Example

ggplot(mtcars) +
geom_point(aes(disp, mpg), color = 'blue', alpha = 0.4)

### Instructions

• set color to 'blue' and alpha to 0.4
# set color to 'blue' and alpha to 0.4
ggplot(mtcars) +
geom_point(aes(disp, mpg), _____, _____)
ggplot(mtcars) +
geom_point(aes(disp, mpg, color = factor(cyl)))
ggplot(mtcars) +
geom_point(aes(disp, mpg, color = hp))
ggplot(mtcars) +
geom_point(aes(disp, mpg), color = 'blue')
ggplot(mtcars) +
geom_point(aes(disp, mpg), color = 'blue', alpha = 0.4)

## Shape

### Example

ggplot(mtcars) +
geom_point(aes(disp, mpg, shape = factor(cyl)))

### Instructions

• map shape to cyl
# set shape to 3
ggplot(mtcars) +
geom_point(aes(disp, mpg), ____)

### Example

ggplot(mtcars) +
geom_point(aes(disp, mpg), shape = 3)

### Instructions

• set shape to 3
# set shape to 3
ggplot(mtcars) +
geom_point(aes(disp, mpg), ____)
# map shape to cyl
ggplot(mtcars) +
geom_point(aes(disp, mpg, shape = factor(cyl)))
# set shape to 3
ggplot(mtcars) +
geom_point(aes(disp, mpg), shape = 3)

## Size

### Example

ggplot(mtcars) +
geom_point(aes(disp, mpg, size = hp))

### Instructions

• map size to hp
ggplot(mtcars) +
geom_point(aes(disp, mpg, ____))

### Example

ggplot(mtcars) +
geom_point(aes(disp, mpg), size = 3)

### Instructions

• set size to 3
ggplot(mtcars) +
geom_point(aes(disp, mpg), ____)
ggplot(mtcars) +
geom_point(aes(disp, mpg, size = hp))
ggplot(mtcars) +
geom_point(aes(disp, mpg), size = 3)

## Fit Line

### Example

ggplot(mtcars, aes(disp, mpg)) +
geom_smooth(method = 'lm', se = FALSE)

### Example

ggplot(mtcars, aes(disp, mpg)) +
geom_smooth(method = 'lm', se = TRUE)

### Example

ggplot(mtcars, aes(disp, mpg)) +
geom_smooth(method = 'loess', se = FALSE)

### Example

ggplot(mtcars, aes(disp, mpg)) +
geom_abline(slope = 29.59985, intercept = -0.04122)

## Fit Line - Practice

### Instructions

ggplot(mtcars, aes(disp, mpg)) +
geom_smooth(_____, _____)

### Instructions

ggplot(mtcars, aes(disp, mpg)) +
geom_smooth(_____, _____)

### Instructions

ggplot(mtcars, aes(disp, mpg)) +
geom_smooth(_____, _____)

### Instructions

ggplot(mtcars, aes(disp, mpg)) +
geom_abline(_____, _____)
ggplot(mtcars, aes(disp, mpg)) +
geom_smooth(method = 'lm', se = FALSE)
ggplot(mtcars, aes(disp, mpg)) +
geom_smooth(method = 'lm', se = TRUE)
ggplot(mtcars, aes(disp, mpg)) +
geom_smooth(method = 'loess', se = FALSE)
ggplot(mtcars, aes(disp, mpg)) +
geom_abline(slope = 29.59985, intercept = -0.04122)