condition mean min max ZT0-3 2.9529425 2.9406 2.965285 ZT4-7 3.721115 3.721115 3.721115 ZT8-11 5.1054949999999995 5.1054949999999995 5.1054949999999995 ZT12-15 0 0 0 ZT16-19 5.5684000000000005 5.5684000000000005 5.5684000000000005 ZT20-23 4.991015 4.991015 4.991015