Hi Jerry,

I noticed my last reply didn't go through. I am trying to calculate the
annualized rate of return for a portfolio over 3 years. If after year 1 the
return is +25%, year 2 -25% and year three +25%, the arthemetic mean gives me
8.33% which is not reality, while the geometric mean is 5.4%. The
multiplication of the the returns plus one should be positive before taking
the nth root. Does this make sense?

Biff

"Jerry W. Lewis" wrote:

How do you want negative numbers handled? The geometric mean is not usually
defined with negative numers, because the nth root of a negative number
(product including an odd number of negatives) is a complex number (involving
the imaginary number i=SQRT(-1)).

Jerry

"Biff" wrote:

I need to calculate a geometric mean for an array of numbers of which some
are negative. The geomean function in Excel does not calculate if there are
negative numbers in the array. I'm not sure what the purprose of the
function is if you can't include negative return numbers, but that is the
fact. Does anyone know how a work around or another way to calculate the
geometric mean with an array of negative numbers included?