Dear R users, I have a data set with time series as continuous (time(day of measurement) = 1,7,14,21...), for each time I have measured height in a total of 100 individuals. I would like to correlate height with chlorophyll content (single measurement per individual), and for that I would like to apply an autoregression model. I have read the help in R about FitARp, however I still do not understand what is z, what is p in that script. My data set looks something like this and I would appreciate any help on this issue. Ind Time Height Chlorophyll 1 1 2.5 2 1 7 2.8 2 1 14 3.1 2 1 21 4.2 2 2 1 2.0 2.3 2 7 2.6 2.3 2 14 3.6 2.3 2 21 4.6 2.3 . . . 100 1 2.6 2.7 100 7 3.4 2.7 100 14 4.2 2.7 100 21 5.3 2.7 Thanks in advance and kind regards Rosario