condition mean min max ZT0-3 17.197375 10.535725 20.75925 ZT4-7 7.713374999999999 7.713374999999999 7.713374999999999 ZT8-11 3.4412200000000004 3.4412200000000004 3.4412200000000004 ZT12-15 5.037135 3.354975 6.719295 ZT16-19 12.27365 12.27365 12.27365 ZT20-23 18.44925 18.44925 18.44925