Respiratory function in children

Tager et al. (1979) were among the first to systematically investigate if respiratory function in children was influenced by smoking or whether the child was exposed to smoking at home. Their primary objective was to examine if children exposed to smoking have lower respiratory function. The dataset contains information on more than 600 children. In this case, the measured outcome of interest is forced expiratory volume (FEV), which is, essentially, the amount of air an individual can exhale in the first second of a forceful breath. The data recorded in the dataset are found in the file fev.txt and include the following variables: FEV (liters), Age (years), the height (Ht, measured in inches), the height squared, Gender (0=female, 1=male), and exposure to smoking status (Smoke, 0 = no, 1 = yes).