Dear all I've got the dataset data:2743;4678;21427;6194;10286;1505;12811;2161;6853;2625;14542;694;11491; 14924;28640;17097;2136;5308;3477;91301;11488;3860;64114;14334 I know from other testing that it should be possible to fit the data with the exponentialdistribution. I tried to get parameterestimates for the exponentialdistribution with R, but as the values of the parameter are very close to 0 i get into troubles. Do you know, what i could do in order to get estimates?How do you choose the starting values? in my opinion it should be around 1/mean(data).
#Parameterestimation with mle() with the log-likelihood funktion of the #exponentialdistribution library(stats4) ll<-function(beta) {n<-24 x<-data2 -n*log(beta)+beta*sum(x)} est<-mle(minuslog=ll, start=list(beta=0.1)) summary(est) #instead of a result, i get: Error in optim(start, f, method = method, hessian = TRUE, ...) : non-finite finite-difference value [1] In addition: There were 50 or more warnings (use warnings() to see the first 50) #with fitdistr() for the exponentialdistribution library(MASS) fitdistr(data2,densfun=dexp,start=list(rate=0.1),lower=6e-06,method="BFGS") #instead of a result, i get Error in optim(start, mylogfn, x = x, hessian = TRUE, ...) : non-finite finite-difference value [1] In addition: Warning messages: 1: bounds can only be used with method L-BFGS-B in: optim(start, mylogfn, x = x, hessian = TRUE, ...) 2: NaNs produced in: dexp(x, 1/rate, log) i'll be very happy for any help i can get to solve this problem thank you! ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html