CCGPS AG 5.9.1 Example 1

The data table at the lower right shows a car’s speed in miles per hour and the car’s fuel efficiency in miles per gallon for each speed. A quadratic regression equation that models this data is given by [math]m(x) = –0.0146x^2 + 1.1802x + 9.1356[/math], where [math]x[/math] is speed in mph and [math]m(x)[/math] is fuel efficiency in mpg. A scatter plot of the data with the graph of this model is shown. Use the given regression model to find the car’s fuel efficiency in miles per gallon when this car is traveling [math]31.1[/math] mph. Compare your answer to the data in the table. Do these values match? Then use the graph to estimate the speed(s) that will result in fuel efficiencies of about [math]25[/math] mpg and [math]40[/math] mpg. Use the model to check your estimates.


GeoGebra Materials Team

Resource Type
estimate  graph  model  quadratic-regression  regression  regression-model  scatterplot 
Target Group (Age)
15 – 18
English (United States)
GeoGebra version
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