A data frame with 25 observations on the following 3 variables.
age
the age of the subject.
fat
the body fat percentage.
sex
a factor with levels female and male.
Details
The data come from a study investigating a new methods of measuring body
composition (see Mazess et al, 1984), and give the body fat percentage
(percent fat), age and sex for 25 normal adults aged between 23 and 61 years.
The questions of interest are how are age and percent fat related, and is
there any evidence that the relationship is different for males and females.