The phrase does not correspond to an official or widely known academic work, book, or verified PDF. It is possible the title is a metaphorical or aspirational reference to the beauty and accessibility of mathematical statistics, rather than a direct citation.
The Simple and Infinite Joy of Mathematical Statistics does not promise that learning statistics is easy. It promises that it is —and, against all odds, joyful. The phrase does not correspond to an official
: Even the best books have typos. A verified list of corrections is maintained on the CU Boulder faculty page to help students avoid confusion during proofs. against all odds