8th Grade Scatter Plots and Association Test Solutions and Scoring (PDF)
This grade 8 scatter plots test answers for 8th Grade covers scatter plots and association (Common Core 8.SP.A.1, 8.SP.A.2), with a free PDF to print.
Use this answer key to score the scatter plots and association test out of 20 points. Each solution shows the full work and a scoring guide, so partial credit can be given fairly when a student shows correct steps but makes an arithmetic slip.
Grade 8 · Common Core State Standards: 8.SP.A.1, 8.SP.A.2
Grade 8 scatter plots test answers: worked solutions
Question 1 – Describe the pattern [3 pts]
Positive, linear, strong: the points rise and lie near a line.
Scoring: 1 point for each description.
Question 2 – Identify an outlier [2 pts]
The outlier is (8, 3). The other seven points rise steadily, but this point is far below.
Scoring: 1 point for the point, 1 point for the explanation.
Question 3 – Predict the association [2 pts]
- Negative (faster speed, less time).
- No association.
Scoring: 1 point each.
Question 4 – Slope of a trend line [3 pts]
\(\frac{61 – 25}{95 – 65} = \frac{36}{30} = 1.2\).
For each 1°F increase, about 1.2 more cones are sold.
Scoring: 1 point for the setup, 1 point for 1.2, 1 point for the meaning.
Question 5 – Use a trend line [3 pts]
\(5.3 \cdot 5 + 47 = 73.5\).
For 20 hours the line gives 153, which is more than the maximum score of 100, so the line should not be used that far outside the data.
Scoring: 1 point for the setup, 1 point for 73.5, 1 point for the explanation.
Question 6 – Compare lines [3 pts]
At \(x = 8\): first line \(-14.4 + 23.7 = 9.3\) near 9.5; second line \(-24 + 30 = 6\), far from 9.5.
Scoring: 1 point for each prediction, 1 point for the conclusion.
Question 7 – Cause [2 pts]
No. Hot weather increases both, so a hidden factor explains the association.
Scoring: 1 point for no. 1 point for a valid hidden factor.
Question 8 – Draw a conclusion [2 pts]
The data fall into two separate groups, so there are two types of cases (for example, two different grade levels).
Scoring: 1 point for the two groups, 1 point for a reasonable interpretation.
Total score
20 points
Key facts behind this grade 8 scatter plots test answers
- Positive association: as x increases, y tends to increase.
- Negative association: as x increases, y tends to decrease.
- Clusters are groups of points; outliers are points far from the pattern.
- A linear association has points near a straight line; nonlinear follows a curve.
- A trend line has about as many points above as below and is close to the points.
How to use this grade 8 scatter plots test answers
Score your test with the point values shown for each question. Then read the worked solution of every question where you lost points and note the method to review.
All Grade 8 chapters: Grade 8 math.
More 8th Grade math
Lessons
See all
Worksheets
See all
Tests
See all
Scientific Notation Test with Point Values- Square Roots and Cube Roots Test with Point Values
- Angles in Triangles and Parallel Lines Test with Point Values
- Volume of Cylinders, Cones and Spheres Test with Point Values
- Distance on the Coordinate Plane Test with Point Values
- Scatter Plots and Association Test with Point Values
