R Programming Language Certification Data Visualization & Reporting 3

Question 1

Which package in R is used to create interactive, web-based visualizations using the Plotly library?

Accepted Answer

plotly

Answer

The plotly R package wraps the Plotly JavaScript library, enabling interactive hover, zoom, and click features in R-generated charts.

Question 2

What does the knitr::kable() function do in R?

Accepted Answer

Generates a formatted table for R Markdown output

Answer

kable() from the knitr package renders a data frame or matrix as a formatted HTML or LaTeX table suitable for embedding in R Markdown documents.

Question 3

Which ggplot2 function controls the color palette for a discrete variable?

Accepted Answer

scale_fill_manual()

Answer

scale_fill_manual() allows manual specification of fill colors for discrete variables by providing a named vector of color values.

Question 4

Which R function renders an R Markdown file to its output format?

Accepted Answer

rmarkdown::render()

Answer

rmarkdown::render() compiles an .Rmd file, executing all code chunks and converting the document to the specified output format via pandoc.

Question 5

In Shiny, which function is used to display a ggplot2 plot in the UI?

Accepted Answer

plotOutput()

Answer

plotOutput() is the UI function that creates a placeholder for a plot, while renderPlot() in the server creates the actual ggplot2 object.

R Programming Language Certification Practice Test