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Problem-Solving and Data Analysis Difficulty: Medium
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In the given scatterplot, a line of best fit for the data is shown.

Which of the following is closest to the slope of this line of best fit?

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Explanation

Choice C is correct. A line of best fit is shown in the scatterplot such that as the value of x increases, the value of y decreases. It follows that the slope of the line of best fit shown is negative. The slope of a line in the xy-plane that passes through the points x1,y1 and x2,y2 can be calculated as y2-y1x2-x1. The line of best fit shown passes approximately through the points 0,8 and 10,1. Substituting 0,8 for x1,y1 and 10,1 for x2,y2 in y2-y1x2-x1 yields the slope of the line being approximately 1-810-0, which is equivalent to -710, or -0.7. Therefore, of the given choices, -0.7 is the closest to the slope of this line of best fit.

Choice A is incorrect. The line of best fit shown has a negative slope, not a positive slope.

Choice B is incorrect. The line of best fit shown has a negative slope, not a positive slope.

Choice D is incorrect and may result from conceptual or calculation errors.