condition mean min max ZT0-3 5.99327213025 5.379176661500001 6.607367599000001 ZT4-7 5.489520495000001 5.086057433000001 5.892983557 ZT8-11 7.993426836 6.613911906333334 9.372941765666667 ZT12-15 9.4326641165 9.321915103 9.54341313 ZT16-19 13.3239837085 13.289681343666667 13.358286073333334 ZT20-23 14.954482056666667 13.497799993333333 16.411164120000002