When trying to find the equation of the straight line which best "fits" a set of points in the plane, one approach is to find the line which minimizes the sum of the squares of the vertical distances between the y-coordinates of the data points and the y-coordinates of the corresponding points on the line. This so-called "least squares" approach produces the "linear regression equation" whose graph is called the "line of best fit." Precise formulas exist for computing the slope and y-intercept of this line, and graphing calculators can handle it in a snap. But for students being presented with the concept for the very first time who may be having a hard time seeing exactly what is going on, this GeoGebra worksheet is a manual, yet very visual approach. As they move sliders or input specific guesses as to what they think the slope and y-intercept of the linear regression equation might be, the graph of the line they produce gives them instant feedback. When they get close enough to the actual line, a congratulatory message appears with the correct answer. If they need a hint, either the slope or the y-intercept can be displayed, greatly simplifying the task.
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