Knowledge Quiz: Presenting Output

Note

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What does wrapping a data frame in knitr::kable() accomplish, compared to letting R print the data frame directly?

It converts the data frame into a figure.It renders the data as a properly formatted table matching the document’s style, rather than R’s plain console-style printout.It changes the underlying values stored in the data frame.It automatically rounds every numeric column to two decimal places.

• Wrong: kable() produces a table, not a figure.
• Correct: kable() produces a clean, document-formatted table instead of R’s raw console output.
• Wrong: kable() only changes how the data is displayed, not the underlying values.
• Wrong: kable() does not automatically round values; rounding must be done separately if desired.

What do the fig-width and fig-height chunk options control?

Whether the figure’s code is shown alongside the plot.The color palette used in the plot.The dimensions of the rendered figure, in inches.The caption text shown below the figure.

• Wrong: showing or hiding code is controlled by echo, not the figure sizing options.
• Wrong: the color palette is determined by the plotting code itself, not by these chunk options.
• Correct: fig-width and fig-height set the rendered figure’s dimensions, in inches.
• Wrong: the caption is set with fig-cap, not fig-width/fig-height.

You include a local image in a page using a plain relative path, images/photo.jpg. The image displays correctly on that page, but breaks when the same image is included from a page in a different folder. What is the most reliable fix?

Rename the image file.Move the image next to every page that uses it.Use a project-relative path with a leading slash, e.g. /assets/images/photo.jpg.Convert the image to a different file format.

• Wrong: renaming the file doesn’t address how the path is resolved.
• Wrong: duplicating the image across folders works but isn’t a reliable or maintainable fix.
• Correct: a leading / makes the path resolve from the project root regardless of which page includes it.
• Wrong: the file format has no bearing on how the path is resolved.

Why is it generally recommended to export figures as vector graphics (e.g., PDF or SVG) rather than a raster format (e.g., PNG or JPEG) for a report?

Vector formats always produce smaller file sizes than raster formats.Vector graphics render crisply at any zoom level or print size, while raster images can look blurry or pixelated when scaled up.Vector graphics load faster in a web browser than raster images.Vector formats are the only ones supported by Quarto.

• Wrong: file size depends on the image’s complexity, not simply on whether it’s vector or raster.
• Correct: vector graphics scale without loss of quality, so they stay sharp when zoomed in or printed at a larger size, unlike raster images.
• Wrong: load time depends on file size and complexity, not simply on vector versus raster format.
• Wrong: Quarto supports both vector and raster image formats.