Algebra
Data and statistics
Scatter plots
20 practice questions
2 video lessons
Theory + worked examples
Theory
A scatter plot graphs paired data \((x,y)\) as points to show the relationship between two variables.
Look for a trend: points rising (positive), falling (negative), or scattered (no association).
A scatter plot of paired data.
Reading a scatter plot.
What to look for:
\[\text{trend, strength, and outliers}\]
An outlier stands away from the pattern.
How to use a scatter plot
- Plot each data pair as a point.
- Look for an overall trend.
- Describe the association.
- Note any outliers.
Example 1 — Read the trend
Points rise from lower-left to upper-right. What association is that?
Solution
As \(x\) increases, \(y\) increases.
| \(\text{positive association}\) |
Example 2 — Plot a point
Where does \((3,5)\) go on a scatter plot?
Solution
Right \(3\), up \(5\).
| \((3,5)\) |
Example 3 — An outlier
What is an outlier on a scatter plot?
Solution
A point that lies far from the overall pattern.
Example 4 — No association
What does a scatter with no pattern show?
Solution
No association between the variables.
Common pitfalls
A trend is not a guarantee for any single point.
Outliers can distort the apparent pattern.
Plot \((x,y)\) correctly — right then up.
Frequently asked questions
What is a scatter plot?
A graph of paired data as points.
What does it show?
The association between two variables.
What is an outlier?
A point far from the overall pattern.
What are the types of association?
Positive, negative, or none.
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