condition mean min max ZT0-3 7.644385 6.70182 9.02003 ZT4-7 3.06761 3.06761 3.06761 ZT8-11 5.83507 5.83507 5.83507 ZT12-15 9.582909999999998 7.10197 12.063849999999999 ZT16-19 8.074085 8.074085 8.074085 ZT20-23 8.2031 8.2031 8.2031