condition mean min max ZT0-3 31.833275 31.2297 32.43685 ZT4-7 31.28575 31.28575 31.28575 ZT8-11 27.570050000000002 27.570050000000002 27.570050000000002 ZT12-15 0 0 0 ZT16-19 39.0549 39.0549 39.0549 ZT20-23 30.20625 30.20625 30.20625