These data are used in the book "Computational Statistics" 
by G.H. Givens and J.A. Hoeting.

Name: toughsmooth.dat
Chapter: 11
Discussed in: Example 11.8

Description: Two hundred predictor-response data points used in
Example 11.8.  These data exhibit a strong pattern, but also severely
non-constant variance.  A variable-span smoother is necessary.

Variable labels: X, Y