Library

Unit 6 - Lesson 6 - Grade 8: Illustrative Mathematics

By Formative Library
Last updated 2 months ago
18 Questions
Note from the author:
Grade 8 Unit 6
Lesson 6: The Slope of a Fitted Line
CC BY 2021 Illustrative Mathematics®
Grade 8 Unit 6
Lesson 6: The Slope of a Fitted Line
CC BY 2021 Illustrative Mathematics®
Lesson: The Slope of a Fitted Line

Estimating Slope (Warm Up)

1.

Estimate the slope of the line.

Describing Linear Associations

For each scatter plot, decide if there is an association between the two variables, and describe the situation using one of these sentences:
  • For these data, as ________________ increases, ________________ tends to increase.
  • For these data, as ________________ increases, ________________ tends to decrease.
  • For these data, ________________ and ________________ do not appear to be related.
2.

3.

4.

Interpreting Slopes

For each of the situations, a linear model for some data is shown.
  1. What is the slope of the line in the scatter plot for each situation?
  2. What is the meaning of the slope in that situation?
5.

y = 5,520.619x - 1,091.303


6.

y = -0.01x + 40.604


7.

y = 0.59x - 21.912


Positive or Negative?

For each of the scatter plots, decide whether it makes sense to fit a linear model to the data. If it does, would the graph of the model have a positive slope, a negative slope, or a slope of zero?
8.

9.

10.

11.

12.

13.

Which of these scatter plots show evidence of a positive association between the variables?

14.

Which of these scatter plots show evidence of a negative association between the variables?

15.

Which do not appear to show an association?

Cool Down: Trends in the Price of Used Cars

Trends in the Price of Used Cars

Here is a scatter plot that shows the years when some used cars were made and their prices in 2016, together with the graph of a linear model for the relationship between year and price.

16.

Is the slope positive or negative?

17.

Which of these values is closest to the slope of the linear model shown in the scatter plot?

18.

Use the value you selected to describe the meaning of the slope in this context.