Two possible approaches come to mind... 1. Create a stepped function using the Overlay Plot. Create a data table with columns for Power and Efficiency. To replicate my results, run the following script: New Table( "Example", Add Rows( 4 ), New Column( "Power", Numeric, "Continuous", Set Property( "Units", "W" ), Set Values( [10, 12, 15, 17] ) ), New Column( "Efficiency", Numeric, "Continuous", Set Property( "Units", "%" ), Set Values( [90, 93, 97, 97] ) ) ); Then create an overlay plot (Graph > Overlay) where Y is Efficiency and X is Power. Finally, click on the red triangle and select Y Options > Step. 2. Add a function to an existing graph. If you already have a graph (such as a Bivariate / Fit Y by X graph) containing data, right-click on the graph and select Customize. In the Customize Graph window, click on the "+" button and paste the following script. Y Function( If( 10 < x <= 12, 90, 12 < x <= 15, 93, 15 < x <= 17, 97, . ), x ); Then click OK.The function should be overlaid on the graph. Adjust axes if necessary. Howard
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