laura bonnett ljbonnettgooglemailcom dear currently working coxph function within package survival model h_ij h_0t exp b1x1 b 2x2 indicator variables follows x1 x2 vps 0 0 ltg 1 0 tpm 0 1 alternative html version deleted ______________________________________________ rhelprprojectorg mailing list httpsstatethzchmailmanlistinforhelp please read posting guide httpwwwrprojectorgpostingguidehtml provide commented minimal selfcontained reproducible code wed 06 aug 2008 123727 0100 r variancecovariance matrix parameter estimates