Section 7.1.2 Problem 7-15

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6 questions
Note from the author:
CPM book 3 Section 7.1.2 problem 7-15
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Problem 7-15a Follow the directions below to create a scatterplot of the data for Melissa.
  • The Odometer Reading will be on the x‑axis and Price on the y‑axis.
  • Move and resize your window so you see the first quadrant only.
  • Plot the data points from the table. Type in each point to graph in (x,y) form.

Now use your graph you created to create a copy on your notecatcher.

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Problem 7-15b Describe the scatterplot you just created.  What do you notice about how the points are placed on the graph?  Do you see any patterns?

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Problem 7-15c Place an additional point on your graph for Nate’s car that has an odometer reading of 23,000 miles.  Explain your strategy for deciding where to put the point.

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Problem 7-15d When a relationship exists, one way to help show a trend in the data is to place a line or curve that, in general, represents where the data falls.  This line, sometimes called a line of best fit, does not need to touch any of the actual data points.  Instead, it shows where the data generally falls.  The line is a mathematical model of the data.  Models of data help you describe the data more easily and help you make predictions for other cars with different mileages.
Decide where a line of best fit could be placed that would best model the data points and add the line.  Are there any limits to where your line makes sense?Problem 7-15

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Problem 7-15e Using the line of best fit, can you predict the price of a car with an odometer reading of 80,000 miles?  If so, explain how the line of best fit helps.  If not, explain why it is not helpful.

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Problem 7-15f Based on the scatterplot, would you agree with Nate’s claim that cars with a higher odometer reading cost less?  Use the scatterplot to justify your answer.