pdf("orlistat.pdf")

orl1 <- read.fwf("C:\\data\\orlistat.dat", width=c(8,8), col.names=c("ffe", "dose"))

orl <- data.frame(ffe=orl1$ffe, dose=orl1$dose)

attach(orl)

orl.nl1 <- nls(ffe ~ b0 + ((b1*dose)/(b2+dose)), start=c(b0=1, b1=1, b2=1))

summary(orl.nl1)

dev.off()