Distribution

Two-dimensional density contour plot

Shows levels of an estimated two-dimensional probability density.

Plot
Distribution
Relationship

What it answers

Where are high-density regions in two dimensions?

Shape: Nested contour lines or regions
What it shows: Modes, spread and joint concentration.

Example

The question

Where are customers most concentrated by age and yearly spend?

Customers by age and yearly spend (density contours, illustrative)

Nested contour lines; the innermost ring is the densest area. One cluster is around age 34 and 700 euros a year, a second, smaller one around age 58 and 1,300 euros.

Illustrative data. It belongs to no company.

When to use it

Use it when

Summarising dense continuous XY clouds.

Avoid it when

Tiny samples or confusing density height with enclosed probability.

How to read it

Read nested density contours and their labelled level meaning.

Note

Levels can mean density heights or enclosed probability. Label the convention.

The data you need

Layout: Long table
Fields: X: number; Y: number
One row is: One observation with paired numeric measurements. What is the grain?
Rules: X and Y must refer to the same observation. Do not independently sort either column.
Optional: Optional ID,Group,Weight. Binning and smoothing settings belong to chart configuration.
Preparation: Align measurements by observation ID, select relevant variables and handle missingness. Scale or standardise only where the analytical method requires it.
Units: State the unit of every coordinate/variable. A unitless transformed or standardised scale must be identified; no common denominator is assumed.

A long table: one row per observation, few columns. New data adds rows.

Worked example

A supplied 50% probability contour encloses half the model's estimated mass. An outer 90% contour covers a larger region; these are not pointwise probabilities.

X	Y
2	10
4	100
6	50

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