Sunday, November 7, 2010

Ch. 2 project

For my Chapter 2 project, I chose the Lexus IS250. I had to find out the mileage for my car at these speeds : (55, 60, 65, 70, 75, 80) and for each of the speeds, the mileages were : (26, 25.2, 23.9, 21.6, 20, 18.7). I then graphed the points and the line showed that it has a negative correlation, which means that the slope is negative. Then I drew the line of best fit. To find the slope, I used the two points (55, 26) & (80, 18.7). The slope I found was -0.29. Using the point slope form, I found the equation y=-0.29x+42. The value of my graph's correlation coefficient of r is -.99. The value of r tells us that the higher the speed is, the lower the mileage would be. The line of best fit equation I found with the calculator is y=-.31x+43.5. The mileage for a speed of 55 miles per hour would be 26.45. The speed is 50 if the mileage is 28 miles per gallon.

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