Four pair-wise sets of data (y ~ x) that have the same basic statsitical properties but greatly differ in graphical form and shape.
Anscombe
A data frame with three variables:
quartet The Anscombe quartet (1th, 2th, 3th, or 4th)
x numeric x variable (integers)
y numeric y variable (continous)
Data gathered from dataset::anscombe
F. J. Anscombe, Graphs in Statistical Analysis. Am. Stat. 27, 17 (1973).