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Cogito

Grade 8 Math · Chapter 10 · Lesson 1

Practice Worksheet

Scatter Plots and Association

Two measurements from the same thing.

10 problems · about 19 minutes · 8.SP.A.1, 8.SP.A.2, 8.SP.A.3

NameDate

Figure — use these to answer the problems

Move the line until it runs through the middle of the points.
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y = x + 1
Slope of your line1
Where it crosses1
Figure 1

Warm-Up Review

From earlier lessons. Loosen up before the new work.

2 problems

  1. From “Volume of Cones, Cylinders, and Spheres”

    A cylinder holds 210. Its matching cone holds?

    Answer

  2. From “Distance Between Two Points”

    From (0, 0) to (8, 15). Distance?

    Answer

Warm Up

Straightforward practice. Get the method working first.

4 problems

  1. Fitted line y = 2x + 3. Predict for x = 6.

    Answer

  2. What does a negative association look like?

    • The points fall to the right.
    • The points rise to the right.

  3. Points rise to the right. Positive or negative?

    • Positive.
    • Negative.

  4. Fitted line y = 3x + 2. Predict for x = 5.

    Answer

Build It Up

The same ideas with more to keep track of.

2 problems

  1. Fitted line y = x + 4. Predict for x = 6.

    Answer

  2. Does association prove cause?

    • No.
    • Yes.

Stretch Yourself

Mixed problems. Work out what kind of question it is before you start.

2 problems

  1. The Direction

    Points fall to the right. What kind of association is that?

    • Negative.
    • Positive.

  2. The Prediction

    A fitted line is y = 2x + 1. What does it predict when x = 4?

    Answer