Interpreting Line of Best Fit

Describe the relationship between the variables.

• There is no relationship between the variables

• As the age increases, the height increases

• As the age increases, the height decreases

• As the height decreases, the age decreases

The scatter plot below shows the relationship between absences and test score. The equation for the line of best fit is y = -0.9x + 34. What is the meaning of −0.9 in the equation?

• The test score tends to be 0.9 times the absences

• For each additional absence, the test score tends to decrease by 0.9

• The equation predicts that zero absences will result in the test score to be 0.9

  
  

• The absences tends to be 0.9 times the test score

The scatter plot below shows the relationship between inches of snow and snow shovels sold. The equation for the line of best fit is y = 0.8x + 1. What is the meaning of 0.8 in the equation?

• The snow shovels sold tends to be 0.8 times the inches of snow

• For each additional inch of snow, the snow shovels sold tends to increase by 0.8

• The equation predicts that zero inches of snow will result in the snow shovels sold to be −0.8

• For each additional inch of snow, the snow shovels sold tends to decrease by 0.8

The scatter plot below shows the relationship between years of experience and points scored. The equation for the line of best fit is y = 0.6x + 4 What is the meaning of 4 in the equation?

• The equation predicts that zero years of experience will result in the points scored to be 4

• The equation predicts that zero years of experience will result in the points scored to be −4

• For each additional year of experience, the points scored tends to increase by 4

• For each additional point scored, the years of experience tends to increase by 4

Which of the following lines represents the line of best fit for the scatter plot?

• A

• B

• C

• D

The equation of this line is y = -2.2x + 12.4. Interpret the meaning of the slope of the line of best fit.

• for each hour of practice, you will make 12.4 mistakes

• without practicing, you would expect to make 12.4 mistakes

• for each hour of practice, the number of mistakes decreases by 2.2

• for each hour of practice, the number of mistakes increases by 2.2

The equation of this line is y = -2.2x + 12.4. Interpret the meaning of the y-intercept of the line of best fit.

• for each hour of practice, you will make 12.4 mistakes

• without practicing, you would expect to make 12.4 mistakes

• for each hour of practice, the number of mistakes decreases by 2.2

• for each hour of practice, the number of mistakes increases by 2.2

The equation of the line shown is y = 1.4x + 55.2

Interpret the meaning of the slope of the line of best fit.

• without studying, the expected test score would be 55.2%

• for every hour studied, test score decreases by 1.4%

• for every hour studied, test score increases by 1.4%

• without studying, the test score would be expected to be 1.4%

Interpret the meaning of the y-intercept of the line of best fit.

• without studying, the expected test score would be 55.2%

• for every hour studied, test score decreases by 1.4%

• for every hour studied, test score increases by 1.4%

• without studying, the test score would be expected to be 1.4%

The y-intercept of this line is 11. This means Mia will make about 11 mistakes if she practices for ______ hours.

• 0

• 1

• 2

• 3