The default numeric format for columns in a new data sheet depends on the first value you enter in a column. If you enter a number, the default format is numeric; if you enter text, the format is alphanumeric.
You can save a different default numeric format for data sheets by selecting a column that contains the desired format, then choosing Save Window Prefs from the Preferences submenu (Options menu). (If the default format you select is a custom format, it appears in the Custom list of the Numeric Format dialog of all new data windows.)
Graph Objects
If you use a default graph format to create a graph, the numeric format of the first column of data plotted for each axis is used. If you use a graph format other than the default, the numeric format is determined by the graph format file.
