Linear Models for Predictions

What is a line of best fit used for?

• To make predictions

• To make the graph look pretty

• To connect the points

• To make it look like you know what you are doing

440 turtles

• 440 turtles

• 40 turtles

• 150 turtles

• 90 turtles

Chang wants to know if he is improving his skill on the cello. He created a scatter plot and drew a line of best fit. If he uses the point (2, 8) and (5, 1.5) from his line, which equation would best represent the line of best fit?

• y = -2.17x + 12.3

• y = 2.17x + 3.77

• y = -0.46x + 9

• y = -2.17x – 9.35

Which of the following situations could be descried by the equation y=120-25x?

• There are 120 people in the football stadium, and 25 more are entering each hour.

• A plumber charges $25 for a house call and $120 per hour.

• A teacher has 120 students. Her third period has 25 students

• There are 120 gallons of water in a tank. It releases water at a rate of 25 gallons per minute

The commission of a sales representative can be modeled by C(x) = 4n - 10, where n is the number of items sold.  If the sales representative sales 30 items, how much commission will they earn?

• $20

• $120

• $5

• $110

The GPA of a student can be predicted using the equation
G(h) = 1.4h + 1.4  where h is the hours the student spends studying.  What is the expected GPA of a student that spends no hours studying?

• 2.4

• 1.4

• not enough information

• 2.8

The scatter plot shows the average yearly consumption of bottled water by people in the United States starting in 1990. Using the line of best fit, predict the average consumption of bottled water in the year 2000?

• 20 gallons

• 18 gallons

• 21 gallons

• 19 gallons

Mr. Van made a graph to represent the time his students spent studying for their test and their actual test score. Which is the correct equation for the line of best fit?

• y = 1.4x + 55

• y = 1.4x – 84

• y = 0.72x + 60

• y = 0.72 + 56

The scatter plot shows the relationship between the number of chapters and the total number of pages for several books.  Use the trend line to predict how many chapters would be in a book with 140 pages. 

• 12 chapters

• 19 chapters

• 14 chapters

• 21 chapters

Which relationship is shown by this scatter plot?

• As the cost goes down, the number sold goes

  down.

• As the cost goes up, the number sold goes

  down.

• As the cost does down, the number sold

  remains the same.

• There is no relationship between cost and the

  number sold.