Use the fit line's equation to predict, and say what its slope and intercept mean

Answer Key - Grade 8 Math Worksheet - Building Confidence

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

1. 1.

   Kira's class found a fit line for practice time and quiz scores. About what score does the model predict for 6 hours of practice a week?

   54
2. 2.

   Luz's garden club fit a line to seedling heights. About how tall does the model say a seedling is 9 days after it is moved outside, in cm?

   23
3. 3.

   Milo fit a line to bike rides: length against time. The helmet is shiny and new. About how many minutes does the model predict for a 7-kilometer ride?

   25
4. 4.

   Noah's jump-rope club fit a line to weeks of practice and jumps in one minute. About how many jumps does the model predict after 7 weeks?

   75
5. 5.

   Pia's class drew a fit line on the bean plant plot. Using the line, about how tall is a plant 5 weeks after planting, in cm?

   19
6. 6.

   Ren's team drew a fit line for practice and free throws. Using the line, about how many free throws go with 7 hours of practice?

   24
7. 7.

   Tala drew a fit line through a plot of short walks. Using the line, about how many blocks go with 8 minutes of walking?

   18
8. 8.

   Zee's music club drew a fit line on its practice plot. Using the line, about how many chords go with 3 minutes of practice a day?

   18
9. 9.

   Ari's class fit the line y = 4x + 30 to practice time (x, in hours a week) and quiz scores (y). What does the 4 mean?

   • The 4 means students who practice 1 more hour a week tend to score about 4 points higher.
   • The 4 means each student practiced about 4 hours a week.
   • The 4 means a student who does not practice tends to score about 4 points.
   • The 4 means every extra hour raises every student's score by exactly 4 points, with no exceptions.
10. 10.

    Bo's garden club fit the line y = 1.5x + 4 to days outside (x) and seedling height in cm (y). What does the 1.5 mean?

    • The 1.5 means a seedling tends to be about 1.5 cm tall on its first day outside.
    • The 1.5 means every seedling grows exactly 1.5 cm each day.
    • The 1.5 means the club measured 1.5 seedlings each day.
    • The 1.5 means seedlings outside 1 more day tend to be about 1.5 cm taller.