condition mean min max ZT0-3 27.972375 27.63455 28.310200000000002 ZT4-7 25.71285 25.71285 25.71285 ZT8-11 20.861800000000002 20.861800000000002 20.861800000000002 ZT12-15 0 0 0 ZT16-19 26.585500000000003 26.585500000000003 26.585500000000003 ZT20-23 27.70515 27.70515 27.70515