condition mean min max ZT0-3 5.751615 5.081275 6.474975000000001 ZT4-7 5.033005 5.033005 5.033005 ZT8-11 3.321015 3.321015 3.321015 ZT12-15 3.9089424999999998 3.776985 4.0409 ZT16-19 4.14865 4.14865 4.14865 ZT20-23 6.3809000000000005 6.3809000000000005 6.3809000000000005