Hi,

I created an process in openLCA. I use ecoinvent processes as inputs. There is a certain range in the input quantities. EG. for one important parameter, values can range from 1 gram to 4 gram, so I use 2,5 grams for the baseline scenario, but I want to perform a Monte Carlo simulation.

My question is: Can I simply calculate a MEAN and STANDARD DEVIATION and choose Normal distribution to input the uncertainty into my process? Or is it necessary to choose Lognormal distribution with GEOMEAN and Geometrical Standard Deviation? Unfortunately, excel does not calculate geometrical standard deviation (and I am not an expert in statistics)

Because in the precursor processes (Ecoinvent) uncertainty is always defined as lognormal distribution.

Is it problematic to "mix" normal and lognormal distribution in one system?