condition mean min max ZT0-3 7.436483 7.436483 7.436483 ZT4-7 8.4729295 8.4729295 8.4729295 ZT8-11 7.644062 7.644062 7.644062 ZT12-15 8.30155 8.30155 8.30155 ZT16-19 8.093152 8.093152 8.093152 ZT20-23 8.549192 8.549192 8.549192