John Tukey

"Far better an approximate answer to the right question, which is often vague, than an exact answer to the wrong question, which can always be made precise."

"The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data."

"The tool that is so dull that you cannot cut yourself on it is not likely to be sharp enough to be either useful or helpful."