condition mean min max ZT0-3 2.4401783333333333 1.34062 3.202635 ZT4-7 3.4952449999999997 3.4952449999999997 3.4952449999999997 ZT8-11 5.39344 5.39344 5.39344 ZT12-15 14.83075 14.123899999999999 15.537600000000001 ZT16-19 11.063575 11.063575 11.063575 ZT20-23 10.660505 10.660505 10.660505