Problem Solving with Trend Lines

The scatter plot shows the the cost of gas per gallon during certain years.

What is the equation for the trend line in slope-intercept form.

• y = .25x + .05

• y = .05x + .25

• y = x + .25

• y = 2x + 1.5x + .25

The scatter plot shows the the cost of gas per gallon during certain years.

What does "x" represent in the equation?

• Number of years since 1970

• Price of gas per gallon

The scatter plot shows the the cost of gas per gallon during certain years.

What does "y" represent in the equation?

• Number of years since 1970

• Price of gas per gallon

The scatter plot shows the the cost of gas per gallon during certain years.

How can the trend line equation be used to predict the cost of gas per gallon in the year 1992?

• Substitute 92 for x in the equation

• Substitute 92 for y in the equation

• Substitute 22 for x in the equation

• Substitute 22 for y in the equation

The scatter plot shows the the cost of gas per gallon during certain years.

Paul want to know when gas would have cost about $1.50 per gallon. What step should he take?

• Substitute 1.50 for y in the equation

• Add 1.50 to the y-intercept of the equation

• Substitute 1.50 for x in the equation

• Add 1.50 to the slope of the equation

The scatter plot shows the the cost of gas per gallon during certain years.

Paul want to know when gas would have cost about $1.50 per gallon. What step should he take?

• Substitute 1.50 for y in the equation

• Add 1.50 to the y-intercept of the equation

• Substitute 1.50 for x in the equation

• Add 1.50 to the slope of the equation

The scatter plot shows the the cost of gas per gallon during certain years.

Use the trend line equation to predict the cost of gas per gallon in 2017.

• $3.50

• $2.60

• $1.70

• $4.40

The scatter plot shows the the cost of gas per gallon during certain years.

Use the trend line equation to determine when gas would cost about $4 per gallon.

• 2040

• 2023

• 2020

• 2045

The manager of Zaxby's collected data to study the relationship between the number of employees working the registers and the amount of time customers waited in line to order. He made a scatter plot and created a trend line with the equation, y = -70x + 300, where y is the total amount of time waited in seconds and x is the number employees working.

What type of association would this situation demonstrate? Explain.

• Positive Association, the increase in working, increases the wait time

• No Association, the number of people working has no effect on how ling you take.

• Negative Association, more workers less wait time. Slope is negative.

The manager of Zaxby's collected data to study the relationship between the number of employees working the registers and the amount of time customers waited in line to order. He made a scatter plot and created a trend line with the equation, y = -70x + 300, where y is the total amount of time waited in seconds and x is the number employees working.

Which best describes the meaning of the slope in the trend line equation?

• Customers waited an additional 70 seconds for every additional employee.

• Customers waited 70 fewer seconds for every additional employee.

• Customers waited an additional second for every 70 additional employees.

• Customers waited 1 fewer for every 70 additional employees.