Hi! I am trying to perform a nonlinear regression using nls in a data.frame where I have a lot of missing values (na's) in the response. I would like to assign zero weight to those values. I have been looking to the nls help page and there is some mention to na.action, with na.omit and na.fail as options, which does not seem to suit me. I need the missing values once my model is doing a numerical integration over values of the independent values where I don't have the information of the response. my best regards, IOsu -------------- next part -------------- An HTML attachment was scrubbed... URL: https://stat.ethz.ch/pipermail/r-help/attachments/20000711/ecd29c90/attachment.html