condition mean min max ZT0-3 1.4274935759999998 1.158822495 1.696164657 ZT4-7 7.4626729237500005 3.4780946875 11.44725116 ZT8-11 22.1213680625 19.125991965 25.11674416 ZT12-15 18.30173225 17.277392145 19.326072355 ZT16-19 19.929182675 18.485374115 21.372991235 ZT20-23 33.8797047475 29.504146285 38.255263209999995