8 a] Explain composition plots with diagram.
Comparison Plots
Comparison plots include charts that are ideal for comparing multiple variables or variables over time. Line charts are great for visualizing variables over time. For comparison among items, bar charts (also called column charts) are the best way to go. For a certain time period (say, fewer than 10-time points), vertical bar charts can be used as well. Radar charts or spider plots are great for visualizing multiple variables for
multiple groups.
Line Chart
Line charts are used to display quantitative values over a continuous time period and show information as a series. A line chart is ideal for a time series that is connected by straight-line segments. The value being measured is placed on the y-axis, while the x-axis is the timescale.
Uses
- Line charts are great for comparing multiple variables and visualizing trends for both single as well as multiple variables, especially if your dataset has many time periods (more than 10).
- For smaller time periods, vertical bar charts might be the better choice.
Example: The following diagram shows a trend of real estate prices (per million US dollars) across two decades. Line charts are ideal for showing data trends:
Bar Chart
In a bar chart, the bar length encodes the value. There are two variants of bar charts: vertical bar charts and horizontal bar charts.
Use
While they are both used to compare numerical values across categories, vertical bar charts are sometimes used to show a single variable over time.
Examples : The following diagram shows a vertical bar chart. Each bar shows the marks out of 100 that 5 students obtained in a test:
Radar Chart
Radar charts (also known as spider or web charts) visualize multiple variables with each variable plotted on its own axis, resulting in a polygon. All axes are arranged radially, starting at the center with equal distances between one another, and have the same scale.
Uses
- Radar charts are great for comparing multiple quantitative variables for a single
group or multiple groups. - They are also useful for showing which variables score high or low within a dataset,
making them ideal for visualizing performance.
Examples: The following diagram shows a radar chart for a single variable. This chart displays data
about a student scoring marks in different subjects:
