>Hi > >I'm analysing fisheries data (number of fish caught per hour) and I have some 0 values. When I log-trans I have to translate the values by hading some value.
I guess you mean you have to do something arbitrary about the zeros before the log transform. The delta distribution is a generalization of the lognormal for the presence of zeros. See: Pennington M. 1983. EFFICIENT ESTIMATORS OF ABUNDANCE FOR FISH AND PLANKTON SURVEYS. Biometrics 39:281-286. If you are interested, i have template worksheets that compute the statistics from delta/lognormal distributions, including confidence bounds, by using Land's theory of linear combinations of the normal mean and variance. You can speak in Spanish to me if you feel more comfortable. Saludos Rubén http://webmail.udec.cl -- * To post a message to the list, send it to [EMAIL PROTECTED] * As a general service to the users, please remember to post a summary of any useful responses to your questions. * To unsubscribe, send an email to [EMAIL PROTECTED] with no subject and "unsubscribe ai-geostats" followed by "end" on the next line in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list * Support to the list is provided at http://www.ai-geostats.org
