What function creates a scatterplot and then adds a small amount of random noise to each point in the plot to make the points easier to find?

The jitter geom is a convenient shortcut for geom_point(position = "jitter"). It adds a small amount of random variation to the location of each point, and is a useful way of handling overplotting caused by discreteness in smaller datasets.

Usage

geom_jitter( mapping = NULL, data = NULL, stat = "identity", position = "jitter", ..., width = NULL, height = NULL, na.rm = FALSE, show.legend = NA, inherit.aes = TRUE )

Arguments

mapping

Set of aesthetic mappings created by aes() or aes_(). If specified and inherit.aes = TRUE (the default), it is combined with the default mapping at the top level of the plot. You must supply mapping if there is no plot mapping.

data

The data to be displayed in this layer. There are three options:

If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot().

A data.frame, or other object, will override the plot data. All objects will be fortified to produce a data frame. See fortify() for which variables will be created.

A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data. A function can be created from a formula (e.g. ~ head(.x, 10)).

stat

The statistical transformation to use on the data for this layer, as a string.

position

Position adjustment, either as a string, or the result of a call to a position adjustment function.

...

Other arguments passed on to layer(). These are often aesthetics, used to set an aesthetic to a fixed value, like colour = "red" or size = 3. They may also be parameters to the paired geom/stat.

width

Amount of vertical and horizontal jitter. The jitter is added in both positive and negative directions, so the total spread is twice the value specified here.

If omitted, defaults to 40% of the resolution of the data: this means the jitter values will occupy 80% of the implied bins. Categorical data is aligned on the integers, so a width or height of 0.5 will spread the data so it's not possible to see the distinction between the categories.

height

Amount of vertical and horizontal jitter. The jitter is added in both positive and negative directions, so the total spread is twice the value specified here.

If omitted, defaults to 40% of the resolution of the data: this means the jitter values will occupy 80% of the implied bins. Categorical data is aligned on the integers, so a width or height of 0.5 will spread the data so it's not possible to see the distinction between the categories.

na.rm

If FALSE, the default, missing values are removed with a warning. If TRUE, missing values are silently removed.

show.legend

logical. Should this layer be included in the legends? NA, the default, includes if any aesthetics are mapped. FALSE never includes, and TRUE always includes. It can also be a named logical vector to finely select the aesthetics to display.

inherit.aes

If FALSE, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. borders().

Aesthetics

geom_point() understands the following aesthetics (required aesthetics are in bold):

  • x

  • y

  • alpha

  • colour

  • fill

  • group

  • shape

  • size

  • stroke

Learn more about setting these aesthetics in vignette("ggplot2-specs").

See also

geom_point() for regular, unjittered points, geom_boxplot() for another way of looking at the conditional distribution of a variable

Examples

p <- ggplot(mpg, aes(cyl, hwy)) p + geom_point()

What function creates a scatterplot and then adds a small amount of random noise to each point in the plot to make the points easier to find?
p + geom_jitter()
What function creates a scatterplot and then adds a small amount of random noise to each point in the plot to make the points easier to find?
# Add aesthetic mappings p + geom_jitter(aes(colour = class))
What function creates a scatterplot and then adds a small amount of random noise to each point in the plot to make the points easier to find?
# Use smaller width/height to emphasise categories ggplot(mpg, aes(cyl, hwy)) + geom_jitter()
What function creates a scatterplot and then adds a small amount of random noise to each point in the plot to make the points easier to find?
ggplot(mpg, aes(cyl, hwy)) + geom_jitter(width = 0.25)
What function creates a scatterplot and then adds a small amount of random noise to each point in the plot to make the points easier to find?
# Use larger width/height to completely smooth away discreteness ggplot(mpg, aes(cty, hwy)) + geom_jitter()
What function creates a scatterplot and then adds a small amount of random noise to each point in the plot to make the points easier to find?
ggplot(mpg, aes(cty, hwy)) + geom_jitter(width = 0.5, height = 0.5)
What function creates a scatterplot and then adds a small amount of random noise to each point in the plot to make the points easier to find?

What function creates a scatter plot?

A scatter plot can be created using the function plot(x, y). The function lm() will be used to fit linear models between y and x. A regression line will be added on the plot using the function abline(), which takes the output of lm() as an argument.

What is a jittered scatterplot?

The “jitter” option is a useful tool to help better visualize the data. “Jitter” adds random noise to the observations before generating the scatterplot, yielding a better visual sense of how many observations have each pair of X and Y values. “Jitter” does not modify the data permanently.

What does the alpha aesthetic do to the appearance of the points on the plot 1 point?

Like color, size, and shape, “alpha” is an aesthetic property that points (and some other plot elements) have, and to which variables can be mapped. It controls how transparent the object will appear when drawn.

When a data analyst notices a data point that is very different from the norm in a scatter plot the best course of action is to _____ the outlier?

Question 5 Fill in the blank: When a data analyst notices a data point that is very different from the norm in a scatter plot, the best course of action is to _____ the outlier. Correct. When a data analyst notices an outlier, the best course of action is to investigate it.