Relationship
Scatterplot matrix / pair plot
Shows pairwise relationships among numeric variables, often with distributions on the diagonal.
- Plot
- Relationship
- Multivariate exploration
What it answers
Which variable pairs show relationships?
- Shape
- Grid of pairwise scatterplots
- What it shows
- Pairwise associations and multivariate outliers.
Example
The question
Which pairs of store measures move together?
Floor space, staff and sales, every pair (scatterplot matrix, illustrative)
Illustrative data. It belongs to no company.
When to use it
Use it when
Exploring several numeric variables jointly.
Avoid it when
Too many variables or too few observations.
How to read it
Read row and column variable names, then compare each scatter cell.
The data you need
- Layout
- Wide observation table
- Fields
- ObservationID: text; V1...Vp: numeric columns
- One row is
- One observation with several measured numeric variables. What is the grain?
- Rules
- Align variables by observation. Decide scaling, missing-data handling and which columns are features.
- Optional
- Optional Group. PCA, clustering and correlations require calculations before rendering their derived results.
- 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.
Worked example
Three variables X, Y, Z for three records produce three unique pairwise relationships. A repeated X-Y pattern can be inspected alongside X-Z.
| ID | V1 | V2 | V3 |
|---|---|---|---|
| A | 10 | 30 | 5 |
| B | 12 | 20 | 8 |
| C | 18 | 25 | 6 |
