GraphLab teaches basic principles and skills for graphing. The program is divided into four lessons: scaling, drawing a "best-fit" straight line, errors, and least-squares fit.
Scaling: Requires students to set the scales for graphs in which the variables that involve direct and inverse proportions and in which the scale involves exponents. Students must provide equally spaced intervals.
Best Fit Line: Students move a line with the mouse and place it so that the best fit of the data is obtained. The slope of the line must agree within 5% of the calculated least-squares-fit line.
Errors: Scientific data can contain either random and/or systematic errors. In this lesson, students must place the line to give a best fit and then decide based on the phenomena being described what kind of errors the data contain.
Least Squares Fit: In this lesson, students draw the least-squares line by minimizing the sum of the squares of the differentials, which is shown on the screen as they place the line on the data. The differentials are also shown to provide a visual sense of the minimization.
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