condition mean min max ZT0-3 4.182695 2.9881599999999997 5.57305 ZT4-7 2.822275 2.822275 2.822275 ZT8-11 2.0699899999999998 2.0699899999999998 2.0699899999999998 ZT12-15 10.33315 9.4582 11.2081 ZT16-19 8.851234999999999 8.851234999999999 8.851234999999999 ZT20-23 9.088935 9.088935 9.088935