The future of data analysis. Annals of Mathematical Statistics 33 (1), (1962), page 13.
Variant: "An approximate answer to the right question is worth a great deal more than a precise answer to the wrong question." "as the renowned statistician John Tukey once reportedly said," according to Super Freakonomics page 224.
Works
The Technical Tools of Statistics
John TukeyFamous John Tukey Quotes
Sunset salvo. The American Statistician 40 (1). Online at http://www.jstor.org/pss/2683137
The Technical Tools of Statistics. The American Statistician 34 (1). Online at https://www.jstor.org/stable/2682374