Dear Shankar, Please find the variance of a lognormal distribution at the following link: http://en.wikipedia.org/wiki/Log-normal_distribution. In the variance formula, the mu is set to zero.
Jean From: [email protected] [mailto:[email protected]] On Behalf Of Shankar Lanke Sent: Friday, February 18, 2011 9:31 AM To: [email protected] Subject: [NMusers] Estimates for Random effects Dear All, I am going through NONMEM manual 5 and I came across How to obtain initial estimates for omega and sigma In chapter 9 they mentioned the additive and ccv model but not about Log Normal model. For Additive y =f +e sigmay = sigma e= rt (r*t is the fraction of its typical value or mean* typical value) var(e) =se^2=(rt )^2 = (r*t) ^2 For CCV y =f +f e sy =f *se=r*t var(e)=se^2= (rt)^ 2 /f^2 but if we identify t with the value of f (whatever it may be), we have ________________________________ then Var(e) = r^2 i.e the fraction of its typical value How we have to estimate for Log normal model. Thank you very much in advance for your feed back. Regards, Shankar Lanke Ph.D. University at Buffalo Office # 716-645-4853 Fax # 716-645-2886 Cell # 678-232-3567
