Linear Models and Scatter Plots

The equation y = -2x + 7 models the amount of gas remaining in a lawnmower after x hours of use since it was filled. What is the meaning of the slope?

• For each hour of mowing, the mower is predicted to use 2 gallons.

• the predicted amount of gas the lawnmower can hold is 2 gallons

• For every two hours of mowing, the mower is predicted to use 7 gallons.

• The predicted amount of gas remaining after 1 hour is 2 gallons.

If I use  the points (3000, 25) and (4000, 20) What is the approximate equation of the trend line?

If I use the points (-3, 0.5) and (2, 2.5), what is the approximate equation of the trend line?

If we use the point (5, 5) and (8, 8), what is the approximate equation of the trend line?

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

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

Jared collected data on the ages and heights of a random sample of elementary school students. If he plots the data on a scatter plot, what relationship will he most likely see between age and height?

• A negative correlation

• No correlation

• A positive correlation

• A constant correlation

The graph shows the weights of dogs and the time it took the same dogs to complete an agility course in seconds.

Which shows the line of best fit for the data?

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A principal wants to predict the number of students who will drop out of school. The equation that represents this data is y = -10x + 216, where x is the # of years & y is the # of students who drop out. Help him predict the number of students who will drop out in 2012.

• 96 students

• 21 students

• 136 students

• 156 students