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For this week’s assignment you’ll be working with penguin data.
Cute penguins
Between 2007 and 2009, researchers collected data on penguins in three islands in the Palmer Archipelago in Antarctica: Biscoe, Dream, and Torgersen. The penguins dataset has data for 342 penguins from 3 different species: Chinstrap, Gentoo, and Adélie. It includes the following variables:
species: The penguin’s species (Chinstrap, Gentoo, and Adélie)
island: The island where the penguin lives (Biscoe, Dream, and Torgersen)
bill_length_mm: The length of the penguin’s bill, in millimeters (distance from the penguin’s face to the tip of the bill)
bill_depth_mm: The depth of the penguin’s bill, in millimeters (height of the bill; distance from the bottom of the bill to the top of the bill)
flipper_length_mm: The length of the penguin’s flippers, in millimeters
body_mass_g: The weight of the penguin, in grams
sex: The sex of the penguin
year: The year the observation was made
As always, make a new or use an existing R Studio project for your assignment.
Download the penguin data set and load it into your quarto script.
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ℹ Use the conflicted package (<http://conflicted.r-lib.org/>) to force all conflicts to become errors
What is the relationship between penguin weight and bill depth? Plot bill depth (bill_depth_mm) on the x-axis and body mass (body_mass_g) on the y-axis. Use geom_point()
Make a new plot that colors these points by species. What can you tell about the relationship between bill depth and penguin weight?
Add a geom_smooth() layer to the plot and make sure it uses a straight line (hint: include method="lm" in the function). What does this tell you about the relationship between bill depth and body mass?
Change the plot so that there’s a single line for all the points instead of one line per species. How does the slope of this single line differ from the slopes of the species specific lines? Why??
What is the relationship between flipper length and body mass? Make another plot with flipper_length_mm on the x-axis, body_mass_g on the y-axis, and points colored by species.
Facet (facet_wrap) the plot by island (island). What does this graph tell you ?
Regression
Does bill depth predict penguin weight? Run a linear regression (lm()) and interpret the estimate and the p.value. Interpret the result in light of previous plots that you have generated.
Run different regression analyses for the different species (use filter()) to subset the data frame.
