Hello all!
I'm having some difficulty addressing a database problem with data of Sizes (cm).
I want to calculate the geometric mean of the values of the size of a number of species in a group of regions. My data set is divided in columns (regions) and lines (species).
When I attempt to calculate the geometric mean in Excel (it's too big a database to easily work it in R), I get a problem with overflow in an intermediate step (the formula being "Potence(Produce(RANGE);1/RangeSize").
There is just too much cells to be multiplied and, as such, I cannot get the geometric mean.
I was wondering, is it correct to calculate the geometric mean in each region and afterwards perform another mean measure (arithmetic mean?) to calculate the geometric mean of the group of regions?
I've been advised to use a Weighted arithmetic mean, since it uses the Sample size as a ponderation.
I hope I've been clear, and would gladly accept any help or advice.
Thank you so much!