Adding error bars to a trace in a graph is easy. On the Traces sheet of the graphs property box in the bottom right is a section dedicated to error bars. Select the trace you would like to add error bars to from the Traces list, then fill in the necessary error bar parameters.
Y Positive: An expression that, when evaluated, determines the length of the positive going error bar in the Y axis. The result should be in the units of axis itself. You can use a constant, or a complex expression. The result should be positive, or the error bar will be upside down.
Y Negative: Identical to Y positive, but applies to the negative going error bar in the Y axis. The result should be positive, even though the error bar is going in the negative direction.
Y End Width: The width in pixels of the cap at the end of the Y error bars.
X Positive: Identical to Y positive but in the X axis.
X Negative: Identical to Y negative but in the X axis.
X End Width: Identical to Y end width but for X error bars.
XY Box: All error bar expressions must be specified and valid for this feature to work. If checked, a box that would outline the error bars with its center on the data point is displayed instead of the error bars.
End Thickness: The thickness in pixels of the end cap of all the error bars.
Line Thickness: The thickness in pixels of the error bar lines (not including the end caps).
