R Programming Language Certification Data Visualization & Graphics in R 2

Question 1

Which ggplot2 geom creates a bar chart by counting occurrences of each category?

Accepted Answer

geom_bar()

Answer

geom_col()

Answer

geom_histogram()

Answer

geom_count()

Question 2

What argument in geom_bar() or geom_col() maps the fill color to a variable?

Accepted Answer

fill inside aes()

Answer

color= argument

Answer

palette= argument

Answer

hue= argument

Question 3

Which function in ggplot2 adds a smooth trend line (e.g., loess or linear) to a plot?

Accepted Answer

geom_smooth()

Answer

geom_line()

Answer

geom_trend()

Answer

stat_fit()

Question 4

What does coord_flip() do in ggplot2?

Accepted Answer

Swaps the x and y axes

Answer

Flips the color scale

Answer

Reverses data order

Answer

Mirrors the plot

Question 5

Which R package extends ggplot2 to create interactive web-based plots?

Accepted Answer

plotly

Answer

shiny

Answer

ggvis

Answer

htmlwidgets

Question 6

In ggplot2, which scale function controls color mapping for continuous variables?

Accepted Answer

scale_color_gradient()

Answer

scale_color_manual()

Answer

scale_color_discrete()

Answer

scale_fill_brewer()