condition mean min max ZT0-3 7.938048 7.938048 7.938048 ZT4-7 8.0787345 8.0787345 8.0787345 ZT8-11 7.367063 7.367063 7.367063 ZT12-15 7.4711775 7.4711775 7.4711775 ZT16-19 7.920269 7.920269 7.920269 ZT20-23 7.5130005 7.5130005 7.5130005