True models do not exist; see René Margritte’s famous painting ‘La trahison des images’ (The Treachery Of Images). And of course George Box:
The Treachery of Images René Magritte, 1928–29; Oil on canvas; Los Angeles County Museum of Art, California
Practical Exercise
Table 6.2 shows results from analyses of 1.2 million elderly patients undergoing surgery. A practical exercise outlines the underlying analyses (SPSS, can also be done in R, see MarkDown to reproduce Fig 6.3).