condition mean min max ZT0-3 2.11783 2.11783 2.11783 ZT4-7 2.3551770000000003 2.3551770000000003 2.3551770000000003 ZT8-11 3.0067399999999997 3.0067399999999997 3.0067399999999997 ZT12-15 3.217245 3.217245 3.217245 ZT16-19 3.808135 3.808135 3.808135 ZT20-23 6.3976500000000005 6.3976500000000005 6.3976500000000005