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From R for Data Science
How many rows are in penguins? How many columns?
> glimpse(penguins)
Rows: 344
Columns: 8
What does the bill_depth_mm variable in the penguins data frame describe? Read the help for ?penguins to find out.
> bill_depth_mm
a number denoting bill depth (millimeters)
Make a scatterplot of bill_depth_mm vs. bill_length_mm. That is, make a scatterplot with bill_depth_mm on the y-axis and bill_length_mm on the x-axis. Describe the relationship between these two variables.
> ggplot(data=penguins, mapping=aes(x=bill_length_mm, y=bill_depth_mm)) + geom_point(mapping=aes(color=species, shape=species)) + geom_smooth(method="lm") + labs(title="Bill Depth and Bill Length", subtitle="Dimensions for Adelie, Chinstrap, and Gentoo", x="Bill Length (mm)", y="Bill Depth (mm)", color="Species", shape="Species") + scale_color_colorblind()
As bill length increases, bill depth decreases
What happens if you make a scatterplot of species vs. bill_depth_mm? What might be a better choice of geom?
Why does the following give an error and how would you fix it?
> ggplot(data = penguins) +
+ geom_point()
Error in `geom_point()`:
! Problem while setting up geom.
ℹ Error occurred in the 1st layer.
Caused by error in `compute_geom_1()`:
! `geom_point()` requires the following missing aesthetics:
x and y
Run `rlang::last_trace()` to see where the error occurred.
There is an error becaus no aesthetics are provided for x and y axes
What does the na.rm argument do in geom_point()? What is the default value of the argument? Create a scatterplot where you successfully use this argument set to TRUE.
na.rm if set to TRUE removes the missing values silently. na.rm is set to FALSE removes the missing values with a warning. The default value is FALSE, and shows the warning message
ggplot(data=penguins, mapping=aes(x=species, y=bill_depth_mm)) + geom_point(mapping=aes(color=species, shape=species), na.rm=FALSE) + geom_smooth(method=”lm”) + labs(title=”Bill Depth and Bill Length”, subtitle=”Dimensions for Adelie, Chinstrap, and Gentoo”, x=”Bill Length (mm)”, y=”Bill Depth (mm)”, color=”Species”, shape=”Species”) + scale_color_colorblind()
geom_smooth()using formula = ‘y ~ x’ Warning messages: 1: Removed 2 rows containing non-finite values (stat_smooth()). 2: Removed 2 rows containing missing values (geom_point()).
Add the following caption to the plot you made in the previous exercise: “Data come from the palmerpenguins package.” Hint: Take a look at the documentation for labs().
> ggplot(data=penguins, mapping=aes(x=bill_length_mm, y=bill_depth_mm)) + geom_point(mapping=aes(color=species, shape=species)) + geom_smooth(method="lm") + labs(caption="Data is from the palmerpenguins package",title="Bill Depth and Bill Length", subtitle="Dimensions for Adelie, Chinstrap, and Gentoo", x="Bill Length (mm)", y="Bill Depth (mm)", color="Species", shape="Species") + scale_color_colorblind()
Recreate the following visualization. What aesthetic should bill_depth_mm be mapped to? And should it be mapped at the global level or at the geom level?
> ggplot(data=penguins, mapping=aes(x=flipper_length_mm, y=body_mass_g)) + geom_point(mapping=aes(color=bill_depth_mm)) + geom_smooth() + labs(caption="Data is from the palmerpenguins package")