On 04/14/2012 05:00 AM, r-help-request at r-project.org wrote:> Hello, > ?I want to estimate weibull parameters with 30% censored data. I have below the code for the censoring > ?but how it must be put into the likelihood equation to obtain the desire estimate is where i have a problem with, > ?can some body help? > ?My likelihood equation is for a random type-I censoring where time for the censored units is different for each unit. > ? > n=50;r=35 > p=0.8;b=1.5 > t<-rweibull(50,shape=p,scale=b) > meantrue<-gamma(1+(1/p))*b > meantrue > d<-meantrue/0.30 > > cen<- runif(50,min=0,max=d) > cen > s<-ifelse(t<=cen,1,0) > sUse the survreg function in the 'survival' package to get the estimates, It uses a location-scale parameterization, read the examples in the manual page, help('survreg'), to see the transformation to and from the form used by rweibull. Terry T.