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R for Data Science 3.5 Exercises

Oct 24, 2023

From R for Data Science

Exercises 3.5

I’m good enough, I’m smart enough, and doggone it, people like me. ~ the disgraced Al Franken

1-Why does this code not work?

my_variable <- 10
my_varıable
#> Error in eval(expr, envir, enclos): object 'my_varıable' not found

The “i” in my_variable is not written correctly when called on the second line.

2-Tweak each of the following R commands so that they run correctly:

libary(todyverse)

ggplot(dTA = mpg) + 
  geom_point(maping = aes(x = displ y = hwy)) +
  geom_smooth(method = "lm)

Correction:

library(tidyverse)

> ggplot(data  = mpg) + 
+     geom_point(mapping = aes(x = displ, y = hwy)) +
+     geom_smooth(aes(x=displ, y=hwy), method="lm")

3-Press Option + Shift + K / Alt + Shift + K. What happens? How can you get to the same place using the menus?

Keyboard Shortcut Quick Reference comes up.

You can use Tools -> Keyboard Shortcuts Help

4-Let’s revisit an exercise from the Section 2.6. Run the following lines of code. Which of the two plots is saved as mpg-plot.png? Why?

my_bar_plot <- ggplot(mpg, aes(x = class)) +
  geom_bar()
my_scatter_plot <- ggplot(mpg, aes(x = cty, y = hwy)) +
  geom_point()
ggsave(filename = "mpg-plot.png", plot = my_bar_plot)

The my_bar_plot plot is saved because on ggsave, plot=my_bar_plot