The Burt data frame has 27 rows and 4 columns.
The “data” were simply (and notoriously) manufactured. The
same data are in the dataset “twins" in the alr3
package, but with different labels.
Usage
Burt
Format
This data frame contains the following columns:
IQbio
IQ of twin raised by biological parents
IQfoster
IQ of twin raised by foster parents
class
A factor with levels (note: out of order):
high;
low;
medium.
Source
Burt, C. (1966)
The genetic determination of differences in intelligence:
A study of monozygotic twins reared together and apart.
British Journal of Psychology57, 137–153.