## Format

A data.frame of 21 obs. of 4 variables:
[,1] |
y |

integer, loss of acid through the stack |
[,2] |

x1 |
integer, air flow |

[,3] |
x2 |

integer, cooling water inlet temperature |
[,4] |

x3 |
integer, acid concentration |

## Source

Lange, K L and Little, R J A and Taylor, J M G, (1989). "Robust
statistical modeling using the $t$ distribution", *J Amer Statist
Assoc*, **84**, 881--896.