Brian There is an immense amount of literature on mixtures of distributions, generally Normal or lognormal. Unfortunately, I don't have my 1974 paper up on the Web yet, but you can see examples of mixtures in my 1993 paper at the conference in Perth WA.
The CLT will not necessarily apply unless the separate populations are completely mixed geographically and the proportions between the components are reasonably constant. Then you might (only might) get some sort of convergence. There was a paper in Math Geol in the late 70s by M W Clark which reviewed mixture papers to that date. PDM MacDonald at MacMaster (Canada) has done a lot of work in the mixture field also. The ability to separate mixed distributions by statistical means in included in our free teaching software, but I am not supposed to mention that. Isobel Clark http://geoecosse.bizland.com/softwares __________________________________________________ Do You Yahoo!? Everything you'll ever need on one web page from News and Sport to Email and Music Charts http://uk.my.yahoo.com -- * 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
