condition mean min max ZT0-3 17.554556666666667 11.095369999999999 21.37675 ZT4-7 13.9956 13.9956 13.9956 ZT8-11 19.864199999999997 19.864199999999997 19.864199999999997 ZT12-15 24.7429 22.6896 26.7962 ZT16-19 23.86215 23.86215 23.86215 ZT20-23 27.67575 27.67575 27.67575