condition mean min max ZT0-3 3.614515 3.437065 3.7919650000000003 ZT4-7 2.378415 2.378415 2.378415 ZT8-11 6.468154999999999 6.468154999999999 6.468154999999999 ZT12-15 0 0 0 ZT16-19 7.02546 7.02546 7.02546 ZT20-23 6.2568 6.2568 6.2568