how do I set a semi-log plot on Excel

Create your chart. Double click on the vertical axis, and on the scale tab, check
the Logarithmic Scale box.

If you decide you want a log-log chart, you need to start with a scatter chart, In a
scatter chart, both axes offer the Logarithmic Scale option.

- Jon
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Jon Peltier, Microsoft Excel MVP
Peltier Technical Services
Tutorials and Custom Solutions
http://PeltierTech.com/
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