Data Visualization - Key Terms and Concepts

Flashcards cover core vocabulary from the data visualization lecture notes, including data ink concepts, table and chart types, and measures of association.

Data visualization

The practice of presenting data visually through tables and charts to help interpret, analyze, and learn from data.

Data-ink ratio

The portion of ink in a table or chart that conveys data, as described by Edward R. Tufte.

Data-ink

Ink in a chart or table that is necessary to convey the data's meaning.

Non-data-ink

Ink that does not contribute to conveying the data in a chart or table.

Edward R. Tufte

Author who introduced the data ink ratio concept and advocates for efficient data visualization.

Table

A grid display for showing numerical values to support precise reference and comparison.

Table design principles

Guidelines for constructing tables, such as avoiding unnecessary vertical lines and using horizontal lines to separate titles from data.

Crosstabulation

A table describing the relationship between two variables.

PivotTable

An Excel feature that creates a crosstabulation and supports data analysis and summarization.

PivotCharts in Excel

Charts that accompany PivotTables to visualize PivotTable data.

Charts

Visual representations of data such as line, bar, column, pie, and scatter charts.

Scatter chart

A chart showing the relationship between two quantitative variables.

Line chart

A chart that connects data points with lines and is useful for time series data.

Bar chart

A chart with horizontal bars for comparing categories.

Column chart

A chart with vertical bars for comparing categories.

Pie chart

A chart that uses slices of a circle to display the proportional parts of a categorical variable.

Three dimensional chart

A chart drawn in three dimensions; can add depth but may distort data.

Bubble chart

A chart that visualizes three variables by using x and y positions and bubble size for a third variable.

Heat map

A two dimensional representation that uses color shades to indicate magnitude.

Stacked column chart

A column chart where segments are stacked to show part-to-whole relationships across categories.

Clustered column chart

A column chart that places multiple series side by side for each category.

PivotChart

A chart linked to a PivotTable to summarize and analyze data with crosstabulation and visualization.

Scatter-chart matrix

A grid of scatter plots showing relationships between multiple variable pairs.

Sparklines

Small inline charts used to show trends within a single cell.

Trendline

A line added to a chart that approximates the relationship between variables.

Time series data

Data collected at successive points in time to analyze trends.

Axis labels

Labels on chart axes that identify data values and improve readability.

Gridlines

Guide lines in a chart; removing unnecessary gridlines can increase data ink.

Covariance

A measure of the linear association between two variables, indicating how they move together.

Sample covariance

Covariance calculated from a sample of data, typically using division by n minus 1.

Population covariance

Covariance calculated for the entire population, using population means.

Correlation coefficient (r)

A standardized, unitless measure of the linear relationship between two variables, ranging from -1 to 1.

Negative linear relationship

When one variable tends to decrease as the other increases (r < 0).

Positive linear relationship

When both variables tend to increase together (r > 0).

No linear relationship

When r is near zero, indicating little to no linear association.

Scatter diagrams

Plots of paired data used to examine the relationship between two variables.

Time series data (revisited)

Data collected over time to observe trends and patterns.