Scatter plots: patterns of association

Answer Key - Grade 8 Math Worksheet

Circle the best answer, or write your answer on the line.

1. Read this first

   Table, quiz score | minutes studied

   72 | 20, 80 | 35, 88 | 45, 91 | 60. On the scatter plot, the minutes studied go across (x) and the quiz scores go up (y).

2. 1.

   Luz's table lists each student's quiz score first, then the minutes studied. Where does the dot for the student who studied 45 minutes go, written as (x, y)?

   (45, 88)
3. 2.

   Jun built a snowman and measured its height each hour of a sunny day. The carrot nose held on bravely. Which sentence describes the association?

   • No association: as the number of hours goes up, the snowman's height tends neither to go up nor to go down.
   • A negative association: as the number of hours goes up, the snowman's height tends to go down.
   • A positive association: as the number of hours goes up, the snowman's height tends to go up.
4. 3.

   Kira recorded the heights of eight classmates and their spelling scores. Which sentence describes the association?

   • A negative association: as the height goes up, the spelling score tends to go down.
   • A positive association: as the height goes up, the spelling score tends to go up.
   • No association: as the height goes up, the spelling score tends neither to go up nor to go down.
5. 4.

   At a walk-a-thon in the park, Pia recorded the laps walked and the minutes taken by eight walkers. One walker wore a dinosaur costume. Which sentence describes the pattern of the dots?

   • A nonlinear association: the dots tend to follow a curve, not one straight line.
   • No association: the dots tend to show no clear pattern.
   • A linear association: the dots tend to stay near one straight ruler line.
6. 5.

   Zee poured a mug of hot cocoa and measured its temperature every five minutes. Which sentence describes the pattern of the dots?

   • A linear association: the dots tend to stay near one straight ruler line.
   • No association: the dots tend to show no clear pattern.
   • A nonlinear association: the dots tend to follow a curve, not one straight line.
7. 6.

   After the lunch bell, Ari counted the kids still on the playground each minute. At one count, another class came out early. Which point is the outlier, written as (x, y)?

   (6, 47)
8. 7.

   Milo's baking club recorded the grams of flour and the number of cookies in each batch. One batch was giant cookies. Which point is the outlier, written as (x, y)?

   (300, 7)
9. 8.

   Kira timed third graders and eighth graders running 400 meters and measured their heights. The dots form two clusters. How many runners are in the cluster of taller runners?

   8
10. 9.

    Luz measured empty shells from two beaches: small clam shells and big scallop shells. The dots form two clusters. How many shells are in the cluster of smaller shells?

    6
11. 10.

    Zee measured the stems and flower widths of tulips and sunflowers in the school garden. How many flowers are in the cluster of taller flowers?

    5