Scatter plots: patterns of association

Answer Key - Grade 8 Math Worksheet - Challenge Me

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

1. 1.

   Noah's music club plotted minutes of guitar practice a day against chord changes made in one minute. Which answer names the association and gives a good reason?

   • No association, because the dots do not all lie exactly on one line.
   • A negative association, because a ruler line through the middle of the dots rises from left to right.
   • A positive association, because a ruler line through the middle of the dots rises from left to right.
   • No association, because 10 dots are too few to show a pattern.
2. 2.

   Pia's running club timed one lap each week of training and plotted the results. The club's cheer got louder every week. Which answer names the association and gives a good reason?

   • No association, because the dots do not all lie exactly on one line.
   • No association, because 10 dots are too few to show a pattern.
   • A positive association, because a ruler line through the middle of the dots falls from left to right.
   • A negative association, because a ruler line through the middle of the dots falls from left to right.
3. 3.

   Ren plotted ten classmates' heights against the minutes each took to finish a paper maze. Which answer names the association and gives a good reason?

   • A negative association, because a ruler line through the middle of the dots falls from left to right.
   • A positive association, because the right-most dot sits higher than the left-most dot.
   • No association, because the left half and the right half of the dots spread over about the same y-values.
4. 4.

   Esme plotted the temperature at kickoff against the goals Esme's team scored in ten soccer games. Which answer names the association and gives a good reason?

   • A positive association, because a ruler line through the middle of the dots rises from left to right.
   • No association, because the left half and the right half of the dots spread over about the same y-values.
   • A negative association, because the right-most dot sits lower than the left-most dot.
5. 5.

   Ari tossed a play ball straight up, filmed it, and plotted its height every two tenths of a second. 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, with no bend.
6. 6.

   Bo counted the kids on the playground each hour after the park opened. It was the first warm day in weeks. Which sentence describes the pattern of the dots?

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

   Kira put a cup of juice in the freezer to make ice pops and checked its temperature every ten minutes. Which sentence describes the pattern of the dots?

   • A linear association: the dots tend to stay near one straight ruler line, going down steadily.
   • A nonlinear association: the dots tend to follow a curve, not one straight line.
   • No association: the dots tend to show no clear pattern.
8. 8.

   Milo's class counted the pencils left in the class box each week. One week, a helper found a lost bag of pencils. Which point is the outlier, written as (x, y)?

   (8, 88)
9. 9.

   Tala timed twelve bike rides of different lengths. On one ride, a strong wind pushed from behind the whole way. Which point is the outlier, written as (x, y)?

   (30, 50)
10. 10.

    At the harbor, Zee measured sailboat lengths and mast heights. One dot is an outlier. How many boats are in the cluster of bigger boats?

    6