XY graphs vs. Grouped graphs of individual values

When you create a new data table, you choose the format of that table.

If you choose an XY table, the table includes a column for entering X values and these are used as the X coordinate when plotting the data. Straighforward.

Grouped tables do not have a column for X values. If you create a XY graph from a Grouped table:

• Prism uses the row numbers as a set of implicit X values. This means the points will be equally spread across the X axis, even if the values you entered are not equally spaced.
• You cannot change the range of the axis.
• You cannot add additional ticks and grid lines at specified X coordinates.

Possible point of confusion. A Grouped table has a column for entry of row titles. Prism sees these as titles or labels, even if you enter numbers in every row. The table below if a Grouped table with no X column. Note that there is no heading "X" and that the labels (numbers) entered in that column are left justified (X values would be right justified). Also note that the values are equally spread across the X axis. Prism doesn't "know" these labels are numbers, so doesn't use the value as a X coordinate. 

 .