Using Linear Models to Make Predictions

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

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

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

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.

__________ allow us to describe data to others, compare data more easily to other data, and allow us to make predictions. For example, mathematical _________ of weather patterns allow us to predict the weather.

• Solution

• Let statement

• Mathematical Sentence

• Models

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 180 pages. 

• 12 chapters

• 15 chapters

• 18 chapters

• 21 chapters

The following scatter plot shows Pam's training as she prepares to run a 6 mile race at the end of the month. Which of the following would be a reasonable approximation for the length of time it would take for her to run 6 miles?

• 50 min

• 80 min

• 45 min

• 60 min

Which graph shows an accurate trend line for the scatter plot?

• Graph A

• Graph B

• Graph C

• Graph D

Based on the trend line for the scatter plot, which of the following amounts is closest to the cost of a 120-minute phone call?

• $10

• $12

• $15

• $20