Types of correlation
Positive, negative, or no correlation β described as strong or weak based on how tight the cloud is.
Positive correlation. As increases, tends to increase. Example: hours studied vs exam mark.
Negative correlation. As increases, tends to decrease. Example: car age vs car value.
No correlation. No clear trend β the dots are scattered.
Strength.
- Strong: dots lie close to a line.
- Weak: dots are spread out, but a trend is still visible.
Worked descriptions.
- "Strong positive correlation" β clear line, rises as rises.
- "Weak negative correlation" β dots loosely trend down-and-right.
- "No correlation" β no consistent trend.
Tip. Cambridge expects two-word descriptions: a STRENGTH (strong / weak) and a TYPE (positive / negative / no). Single-word answers lose marks.
- Positive: , .
- Negative: , .
- None: no pattern.
- Strong / weak based on tightness.