Hi: I have a data set that I would like to analyze with PROC MIXED. I have used this procedure before, but never with a model with as many levels as this one. I am hoping you can tell me how to set it up (SAS 9.3).   My data consist of enamel formation rate measurments taken sequentially at points along the tooth in three different regions (top third, middle third, and bottom third).   Each tooth is a canine tooth from a single individual, so each "subject" is represented by one canine tooth.   Sequential measurements along a tooth are chronological: measurements at the top represent the rate of enamel formation at an earlier period than measurements at the bottom.   Each subject is either a male or female and is also either a chimpanzee, gorilla, orangutan, or human.   Here is what I am interested in knowing: 1.What is the effect of subject, tooth region (top, middle, bottom thirds), sex (M/F), and species (chimp/gorilla/orangutan/human) on these measurements when each of the other factors is accounted for? 2, How do these measurments change from the top of the tooth to the bottom of the tooth in the teeth of different individuals, sexes and species?   Thanks for any help pointing me in the right direction.   Best, Catena     ... View more