To address these problems, an online tutorial was developed. This tutorial guides students through the construction of a spreadsheet that performs least-squares analysis to find the best-fit line through a series of data points. These calculations can be performed automatically in many spreadsheets, but here we use a somewhat longer process. This has two benefits for students: they can see what the high-level functions are doing, and they learn how to translate an equation into a series of calculations that can be implemented with a spreadsheet. After working through the tutorial, the students have constructed a spreadsheet that will serve them throughout the remainder of the semester, and have also gained significant exposure to the use of spreadsheets.

The tutorial comprises several parts. First, there is the Excel tutorial Using the Least-Squares Method To Calculate Unknown Concentrations and Error (Figure 1). This is a Macromedia flash file that can be embedded as an object in any Web-enabled course, and it is easily accessible and functional on common Web browsers on both the PC and Mac platforms. The tutorial runs about 15 minutes.

Sample problem sets with imperfect data (some points saturating detectors, simulation of swapped standard vials, standards prepared at concentrations below the detection limit), a copy of a calibration lab exercise, and an additional instructor handout are also provided to aid instructors in implementing this tutorial in their courses.