Infants were enrolled at birth in a study of fluoride intake and followed through 
9 months of age. Total fluoride intake was measured at months 1.5, 3, 6, and 9.
There are 1,363 infants.

id 
age 		age of infant (months)
sex 		1=male, 0=female
race		1=white, 0=non-white
momage 		1=30+ years, 0=less than 30 years
momedu1	 	1=HS only, 0=otherwise
momedu2         1=college grad, 0=otherwise
first 		1=infant is first child, 0=otherwise
twokids 	1=two kids at home, 0=otherwise
threekids 	1=3+ kids at home, 0=otherwise 
income 		family income 1=$30,000+, 0=less than $30,000
flouride	fluoride intake (mg/kg)

The rows correspond to each visit for each infant and are given from first visit
to last visit; missing values are shown with a '.'. 

This data set is from Davis (2002) Statistical Methods for the Analysis of
Repeated Measurements. New York: Springer Verlag Inc. Problem 9.10.