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Working with Fitted Lines

3.2.5 Working with Fitted Lines

3.2.5 • Working with Fitted Lines

Cool Down

1.

Which of these scatter plots shows data that would best be modeled with a linear function? Be prepared to show your reasoning.

Graph A

A scatter plot showing points representing weight (milligrams) on the y-axis and height (millimeters) on the x-axis, with values ranging from 0–22 for weight and 0–10 for height.)

Graph B

Scatter plot showing a negative correlation between precipitation (cm) on the x-axis and water used for irrigation (thousands of gallons) on the y-axis; as precipitation increases, irrigation water use decreases.

Compare your answer:

Graph B. Your answer may vary, but here is a sample. The points in scatter plot B seem to follow the shape of a line of best fit. The points in scatter plot in A are very spread out.

2.

Which of the following lines is most likely the line of best fit for the data provided in the graph and table below?

  1. y = − 0.51 x + 225.12 y = − 0.51 x + 225.12

  2. y = 0.34 x − 34.05 y = 0.34 x − 34.05

  3. y = 0.13 x − 0.19 y = 0.13 x − 0.19

  4. y = 0.98 x − 21.13 y = 0.98 x − 21.13

A scatter plot showing the relationship between the number of trees (x-axis) and oxygen produced in tons (y-axis), with points trending upward as the number of trees increases.)
number of trees in a forest tons of oxygen produced by the forest
148 16.43
175 25.64
190 23.28
200 29.2
202 21.41
425 60.56
505 50.75
528 74.45
562 62.66
585 84.24

Compare your answer:

y = 0.13 x − 0.19 y = 0.13 x − 0.19