February, 2003
© 2000, 2001, 2003 Scott S. Emerson, M.D., Ph.D.
Comparing geometric means (e.g.,
Lognormal probability
model-- log outcome is normal)
Continuously distributed, skewed outcome:
·e.g., serum cholesterol, PSA
Outcome summarized by (log) geometric mean (median)
response
Compare groups by (log) ratio of geometric means (medians)
Information measured by within group variance of log
transformed response