Documentation for fev.dat

It is now widely believed that smoking tends to impair lung function.
Much of the data to support this claim arises from studies of
pulmonary function in adults who are long-time smokers. A question
then arises whether such deleterious effects of smoking can be
detected in children who smoke. To address this question, measures
of lung function were made in 654 healthy children seen for a routine
check up in a particular pediatric clinic. The children participating
in this study were asked whether they were current smokers.

A common measurement of lung function is the forced expiratory
volume (FEV), which measures how much air you can blow out of your lungs
in one second. A higher FEV is usually associated with better 
respiratory function. It is well known that prolonged smoking diminishes
FEV in adults, and those adults with diminished FEV also tend to have 
decreased pulmonary function as measured by other clinical variables, 
such as blood oxygen and carbon dioxide levels.

The data set fev.dat contains the
654 children's data in free field format.
Available data includes measurement of age, height, sex, FEV, and
whether each child smokes or not. The format of the data is

SEQNBR = case number
SUBJID = subject identification number
AGE    = subject age at time of measurement (years)
FEV    = measured FEV (liters per second)
HEIGHT = subject height at time of measurement (inches)
SEX    = subject sex (1 = male, 2 = female)
SMOKE  = smoking habits (1 = yes, 2 = no)