condition mean min max ZT0-3 1.932245 1.932245 1.932245 ZT4-7 1.6557050000000002 1.6557050000000002 1.6557050000000002 ZT8-11 1.3507500000000001 1.3507500000000001 1.3507500000000001 ZT12-15 1.166092 1.166092 1.166092 ZT16-19 1.453265 1.453265 1.453265 ZT20-23 1.25712 1.25712 1.25712