1. Input your data in Excel.
   
   
2. Select data that you want to plot and click at Insert and choose a type of graph that you want to plot. In this case I choose the scatter one.
   
   
3. Right click on a data series that you want to put on the second y-axis and click at Format Data Series....
   
   
4. At Series Options choose Secondary Axis and Close.
   
   
5. You will see a graph with two y-axis. You can change other parameters just like a regular graph.
   
   
6. You can even choose different type of graph for each data series by right clicking on it and choose Change Series Chart Type.... Then choose the Chart Type that you want. Just make sure it makes sense. :-)
   
   
   
   

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