Melissa Partyka, research ecologist at the Western Center for Food Safety at the University of California-Davis, has provided simple instructions for calculating your geometric mean below. Geometric Mean (GM) is the average of your log-transformed results. While any base can be used, most growers use log base 10 to perform their transformations. Numbers can be transformed using a calculator, or in a spreadsheet which allows for multiple transformations at the same time. In a calculator, type in your test result and press the ‘log’ button. If you type in 10 and press ‘log’, you should see ‘1’, if you type […]