1.0 KiB
1.0 KiB
(Chapter 8, STAT 1040)
Correlation
Scatter Diagrams
A scatter diagram or scatter plot shows the relationship between two variables. One variable is on the X axis, the other on the Y axis.
Association
- Positive association is demonstrated when the dots are trend upward as
xincreases. - Negative association is demonstrated when the the dots trend downward as
xincreases. - Strong association is demonstrated when dots are clustered tightly together along a line.
- Weak association is demonstrated when dots are not clustered tightly.
Correlation
Correlation is between -1 and 1. Correlation near 1 means tight clustering, and correlation near 0 means loose clustering. r is -1 if the points are on a line with negative slope, r is positive 1 if the points are on a line with a positive slope. As |r| gets closer to 1, the line points cluster more tightly around a line.
Terminology
| Term | Definition |
|---|---|
r |
Correlation Coefficient |
| Linear Correlation | Measures the strength of a line |