Column Selection

The multi-column ASCII, Excel, Lotus, Quattro Pro, SigmaPlot, dBase, SPSS, Systat, and multi-column DIF options use a common column selection procedure.

• The first selection is automatically assigned to the X column and the second is automatically assigned to the Y column.

• A weights column can then be specified, or the X and Y columns respecified, by selecting the desired column and then clicking on the X Values, Y Values, or Weights buttons.

• If the SD Wts box is checked, each weight value is assumed to consist of the standard deviation associated with multiple Y measurements at each particular X value. When this box is checked, the imported column must consist of SD values. The data table weights will consist of 1/SD². Error Bars will then be available in the curve-fit graphs.

• To preview the data to be imported, the Import Preview button must be checked. The graphical preview is automatic. Graphs are shown once both a valid X and valid Y have been selected. The number of valid points is shown just below the graph. The graph's format is fixed.