Name ___________________________________________ A1

Scatter Plot What is it? What are some characteristics?

Line of Best Fit What is it? What are some characteristics?

Which of the three lines is the line of best fit for the provided data?

Unit 4

4-5 Scatter Plots &

Lines of Best Fit

Example 1: The scatter plots below display the same data about the ages of eight health club members and their heart

rates during exercises.

a) Which line is a better fit for the data? Why?

b) Write the equation of the line of best fit you chose in (a). Tell what the slope and y-intercept represent in terms of the

data it models.

Example 2: The scatter plot below shows the relationship between scores on two different quizzes for ten students in a

math class.

a) Drawn on the graph are two possible lines of best fit. Which is a better line of best fit,

line A or line B? Why?

b) Write the equation of the trend line you chose in part (a). Tell what the slope and

y-intercept represent in terms of the data it models.

Example 3: The table and graph below show the predicted annual cost for a middle income family to raise a child from

birth until adulthood. Draw in a line of best fit and write the equation to represent said line.

Child’s Age 3 6 9 12 15

Annual Cost ($) 10,700 11,700 12,600 15,000 16,700

Explain the meaning of the slope and the y-intercept as it relates to the data it represents.

Example 4: The table and graph below give the number of hours spent studying for a math final exam, and the actual

final exam grade. Draw in a line of best fit and write the equation to represent said line.

Study Hours 3 2 5 1 0 4 3

Final Exam Grade 84 77 92 70 60 90 75

Explain the meaning of the slope and the y-intercept as it relates to the data it represents.