simulating survival data according to covariate values
I'd like to simulate survival times according to continuous covariate values. Suppose we have a continuos covariate whose value of zero corresponds to a mean survival time of 180 days and whose value of 0.5 corresponds to a mean survival time of 240 days. How can I use this information to simulate survival times according to the covariate information? I guess I have to use distribution functions like rexp or rweibull? How can I use them to include this information on the covariates?
I'd be very glad for helpful information!