Data Visualization Test #2

Question 1

In a data.frame, which of the following lists the names of variables?

Accepted Answer

quantile()

Answer

The `quantile()` function in R is used to calculate quantiles for numeric variables, providing key summary statistics about their distribution. While it doesn't directly 'list' variable names, it operates on the *data within* variables, and its application across multiple variables helps characterize and understand the nature of each variable in a data.frame.

Question 2

Remove the table's grid lines and the chart's horizontal lines.

Accepted Answer

increases the data-ink ratio

Answer

The data-ink ratio, a principle by Edward Tufte, emphasizes maximizing the proportion of ink used to display actual data. Removing non-essential elements like grid lines and horizontal lines eliminates 'non-data ink' from a chart. This action increases the relative amount of ink dedicated to conveying information, thereby improving the data-ink ratio and making the visualization clearer and more efficient.

Question 3

_________ is used to search for and alter graphical settings.

Accepted Answer

par()

Answer

In R's base graphics system, the `par()` function is the primary tool for searching for and altering graphical settings. It allows users to control a wide range of plot parameters, such as margins, colors, fonts, and the layout of multiple plots on a single device. This function is essential for customizing the appearance of visualizations.

Question 4

The useful chart is a great way to show numerous variables.

Accepted Answer

scatter chart matrix

Answer

A scatter chart matrix, also known as a pairs plot, is an excellent visualization for exploring relationships among numerous variables simultaneously. It displays a grid of scatter plots, showing every possible pair of variables against each other. This comprehensive view helps in quickly identifying correlations, trends, and outliers across multiple dimensions of a dataset.

Question 5

Which of the following is a tool for determining whether or not something is normal?

Accepted Answer

qqline()

Answer

The `qqline()` function in R is specifically used to add a reference line to a Q-Q (quantile-quantile) plot. This line typically passes through the first and third quartiles of the data and serves as a visual guide to assess whether the data points follow a specific theoretical distribution, most commonly a normal distribution. If the data points align closely with the `qqline`, it suggests normality.

Data Visualization Practice Test

Data Visualization Practice Test

Data Visualization Test #2