Learning outcomes
- describe association using standard statistical language
- distinguish positive, negative, and no clear association
- recognize strength and form
- identify outliers in a scatterplot
Four common description words
Direction
- positive
- negative
- no clear direction
Form
- linear
- curved
- no clear form
Strength
- strong
- moderate
- weak
Unusual features
- outliers
- clusters
- gaps
Examples
- strong positive linear association
- weak negative association
- no apparent association
Why wording matters
- Statistics answers should be precise.
- Saying “they are connected” is weaker than saying “there is a moderate positive linear association.”
Exam hints and traps
- Strong does not mean steep; it means points stay close to a pattern.
- Positive means y tends to increase as x increases.
- A curved pattern is not linear even if the relationship is strong.
- Outliers can distort interpretation.
Quick practice
- What does positive association mean?
- Can a relationship be strong but curved?
- What is an outlier?
Answer key
- As one variable increases, the other tends to increase
- Yes
- A point far from the general pattern