The frets data frame has 25 rows and 4 columns.

The data consist of measurements of the length and breadth of the heads of pairs of adult brothers in 25 randomly sampled families. All measurements are expressed in millimetres.

frets

Format

This data frame contains the following columns:

l1

The head length of the eldest son.

b1

The head breadth of the eldest son.

l2

The head length of the second son.

b2

The head breadth of the second son.

Source

The data were obtained from

Frets, G.P. (1921) Heredity of head form in man. Genetica, 3, 193.

References

Davison, A.C. and Hinkley, D.V. (1997) Bootstrap Methods and Their Application. Cambridge University Press.

Whittaker, J. (1990) Graphical Models in Applied Multivariate Statistics. John Wiley.