NumicornNumicornLearn, solve, progress

Bivariate Data and Scatter Plots Practice Tests

These Grade 8 Math practice tests cover paired numerical data, scatter plots, positive and negative associations, trends, line of best fit, residuals, outliers, and predictions.

Skills covered

  • Reading ordered pairs, tables, domains, and ranges
  • Describing positive, negative, weak, strong, and no association
  • Interpreting clusters, outliers, trend lines, and residuals
  • Distinguishing interpolation, extrapolation, association, and causation
  • Using real-world data to make and evaluate predictions

How to use these practice tests

Read both axes and their units first. Then describe the direction and strength of the association, inspect unusual points, and use a trend line only within a reasonable data range.

For more Grade 8 Math practice, return to the Grade 8 Math category.

Select a test

5 Tests
1. Test2. Test3. Test4. Test5. Test

3. Test

Grade 8 Bivariate Data and Scatter Plots Practice Tests

Practice Grade 8 Math questions about bivariate data, scatter plots, associations, trend lines, residuals, outliers, predictions, and real-world contexts.

Choose the best answer for each question. Identify both variables, read the scale, describe the association, and distinguish association from causation.

10 Questions
0/10 Questions0 %
Correct 0
Incorrect 0
Unanswered 10
1. QuestionMultiple choice

A line of best fit is used mainly to:

Please select an answer first.

Correct answer: A

The correct answer is Describe a trend and make predictions..

  1. Identify the two variables: Name the input and output variables and read each ordered pair, table, or graph carefully.
  2. Analyze the association: A trend line summarizes the pattern and can be used for estimates.
  3. Check the prediction: Decide whether the conclusion is interpolation, extrapolation, association, causation, or an observation about an outlier.

A trend line summarizes the pattern and can be used for estimates.

2. QuestionMultiple choice

Estimating a value inside the range of observed data is called:

Please select an answer first.

Correct answer: B

The correct answer is Interpolation.

  1. Identify the two variables: Name the input and output variables and read each ordered pair, table, or graph carefully.
  2. Analyze the association: Interpolation predicts within the observed input range.
  3. Check the prediction: Decide whether the conclusion is interpolation, extrapolation, association, causation, or an observation about an outlier.

Interpolation predicts within the observed input range.

3. QuestionMultiple choice

Estimating a value beyond the range of observed data is called:

Please select an answer first.

Correct answer: C

The correct answer is Extrapolation.

  1. Identify the two variables: Name the input and output variables and read each ordered pair, table, or graph carefully.
  2. Analyze the association: Extrapolation extends a trend beyond the observed data range.
  3. Check the prediction: Decide whether the conclusion is interpolation, extrapolation, association, causation, or an observation about an outlier.

Extrapolation extends a trend beyond the observed data range.

4. QuestionMultiple choice

A scatter plot has one point far above the main pattern. What is that point called?

Please select an answer first.

Correct answer: D

The correct answer is An outlier.

  1. Identify the two variables: Name the input and output variables and read each ordered pair, table, or graph carefully.
  2. Analyze the association: A point separated from the overall pattern is an outlier.
  3. Check the prediction: Decide whether the conclusion is interpolation, extrapolation, association, causation, or an observation about an outlier.

A point separated from the overall pattern is an outlier.

5. QuestionMultiple choice

Why can an outlier affect a line of best fit?

Please select an answer first.

Correct answer: A

The correct answer is It can pull the trend line away from the main cluster..

  1. Identify the two variables: Name the input and output variables and read each ordered pair, table, or graph carefully.
  2. Analyze the association: A distant point can influence the line and change predictions.
  3. Check the prediction: Decide whether the conclusion is interpolation, extrapolation, association, causation, or an observation about an outlier.

A distant point can influence the line and change predictions.

6. QuestionMultiple choice

A trend line predicts y=30 when x=5. What is the predicted output?

Please select an answer first.

Correct answer: B

The correct answer is 3030.

  1. Identify the two variables: Name the input and output variables and read each ordered pair, table, or graph carefully.
  2. Analyze the association: The predicted output is the y-value given by the trend line at x=5.
  3. Check the prediction: Decide whether the conclusion is interpolation, extrapolation, association, causation, or an observation about an outlier.

The predicted output is the y-value given by the trend line at x=5.

7. QuestionMultiple choice

A trend line is y=2x+4y=2x+4. What does it predict when x=6x=6?

Please select an answer first.

Correct answer: C

The correct answer is 1616.

  1. Identify the two variables: Name the input and output variables and read each ordered pair, table, or graph carefully.
  2. Analyze the association: Substitute 6: y=2(6)+4=16y=2(6)+4=16.
  3. Check the prediction: Decide whether the conclusion is interpolation, extrapolation, association, causation, or an observation about an outlier.

Substitute 6: y=2(6)+4=16y=2(6)+4=16.

8. QuestionMultiple choice

If a data point lies below a line of best fit, what does that mean?

Please select an answer first.

Correct answer: D

The correct answer is Its observed y-value is less than the predicted y-value..

  1. Identify the two variables: Name the input and output variables and read each ordered pair, table, or graph carefully.
  2. Analyze the association: The vertical position below the line means the actual output is smaller than the model prediction.
  3. Check the prediction: Decide whether the conclusion is interpolation, extrapolation, association, causation, or an observation about an outlier.

The vertical position below the line means the actual output is smaller than the model prediction.

9. QuestionMultiple choice

A model predicts 72 visitors, and 68 visitors are observed. What is the residual observed minus predicted?

Please select an answer first.

Correct answer: A

The correct answer is −4-4.

  1. Identify the two variables: Name the input and output variables and read each ordered pair, table, or graph carefully.
  2. Analyze the association: Residual = observed - predicted = 68−72=−468-72=-4.
  3. Check the prediction: Decide whether the conclusion is interpolation, extrapolation, association, causation, or an observation about an outlier.

Residual = observed - predicted = 68−72=−468-72=-4.

10. QuestionMultiple choice

When is interpolation usually more reliable than extrapolation?

Please select an answer first.

Correct answer: B

The correct answer is When the prediction stays within the observed data range..

  1. Identify the two variables: Name the input and output variables and read each ordered pair, table, or graph carefully.
  2. Analyze the association: Predictions within the data range are supported by observed points on both sides.
  3. Check the prediction: Decide whether the conclusion is interpolation, extrapolation, association, causation, or an observation about an outlier.

Predictions within the data range are supported by observed points on both sides.

Previous testNext test