condition mean min max ZT0-3 7.5646 7.5646 7.5646 ZT4-7 6.934175 6.934175 6.934175 ZT8-11 6.43106 6.43106 6.43106 ZT12-15 6.073975000000001 6.073975000000001 6.073975000000001 ZT16-19 7.832129999999999 7.832129999999999 7.832129999999999 ZT20-23 6.97168 6.97168 6.97168