Dataset: PUPILRAWDATA2 ### linear interpolation ### reference - http://stackoverflow.com/questions/16011790/add-missing-xts-zoo-data-with-linear-interpolation-in-r Jill2 <- zoo(JillTS) Jill2 Jill3 <-na.approx(object=Jill2) Jill3TZ <-as.ts(Jill3) ## original Eliz plot with interpolated Jill (Jill3TZ) plot(ElizTS, ylim=c(2,8), col="blue", frame=FALSE, ylab="Pupil Dilation (mm)") lines(Jill3TZ, col="red") ## comparing original Jill (JillTS) and interpolated Jill (Jill3TZ) plot(JillTS, ylim=c(2,8), col="blue", frame=FALSE, ylab="Pupil Dilation (mm)", lwd=3) lines(Jill3TZ, col="red", ylim=c(2,8), lty="dashed")