Lesson 7Observing More Patterns in Scatter Plots

Learning Goal

Let’s look for other patterns in data.

Learning Targets

  • I can pick out clusters in data from a scatter plot.

  • I can use a scatter plot to decide if two variables have a linear association.

Lesson Terms

  • negative association
  • outlier
  • positive association

Warm Up: Notice and Wonder: Nonlinear Scatter Plot

Problem 1

What do you notice? What do you wonder?

A scatter plot of oil production (thousands of tons) vs crude oil import price (dollars per barrel). Data starts high on the left, then drops down and levels out.

Activity 1: Scatter Plot City

Problem 1

Your teacher will give you a set of cards. Each card shows a scatter plot.

  1. Sort the cards into categories and describe each category.

  2. Explain the reasoning behind your categories to your partner. Listen to your partner’s reasoning for their categories.

  3. Sort the cards into two categories: positive associations and negative associations. Compare your sorting with your partner’s and discuss any disagreements.

  4. Sort the cards into two categories: linear associations and non-linear associations. Compare your sorting with your partner’s and discuss any disagreements.

Activity 2: Clustering

Problem 1

How are these scatter plots alike? How are they different?

4 scatter plots. A-data has a negative correlation. B-2 clusters of data with a positive correlation. C-a sideways V opening on the right. D-2 clusters with negative correlation

Lesson Summary

Sometimes a scatter plot shows an association that is not linear:

A scatter plot with data that makes somewhat of a U shape

We call such an association a non-linear association. In later grades, you will study functions that can be models for non-linear associations.

Sometimes in a scatter plot we can see separate groups of points.

A scatter plot with 2 clusters of data with a positive correlation. A second graph with the same data but a circle around each cluster.

We call these groups clusters.