5 Data Visualization Free Online FlashCards

What is the purpose of data visualization?

Data visualization uses visual elements such as position, length, lines, and color to make patterns and comparisons easier to see.

Which charts are useful for comparing categories?

Use a bar chart or dot plot to compare values across categories.

Why should bar charts usually start at zero?

Use a common baseline, usually zero, so bar lengths represent values honestly.

What does each bar in a histogram represent?

A histogram groups numerical values into intervals, called bins; each bar shows how many observations fall in a bin.

How can bin width affect a histogram?

Changing bin widths can change a histogram’s apparent shape, so choose and label them carefully.

What does a box plot summarize, and what can it hide?

A box plot summarizes a distribution with its median, quartiles, and whiskers, but does not show every detail.

When is a line chart appropriate, and how should time be ordered?

Use a line chart for values measured over time or another ordered, continuous scale; put time in chronological order on the horizontal axis.

When should points not be connected by lines?

Avoid connecting points when their order has no meaningful continuity.

How does a scatter plot represent two numerical variables?

Use a scatter plot: place one numerical variable on each axis, with each point representing an observation.

Does a pattern in a scatter plot prove causation?

An upward or downward pattern suggests an association, but does not by itself show that one variable causes the other.

What should you check in the data before making a chart?

Check units, missing values, category labels, time intervals, and whether values are counts, rates, or percentages.

Which visual encodings support more precise comparisons?

For precise comparisons, position and length are generally easier to judge than area or volume.