condition mean min max ZT0-3 2.6128316666666667 2.484855 2.707845 ZT4-7 2.843615 2.843615 2.843615 ZT8-11 3.837975 3.837975 3.837975 ZT12-15 5.153665 3.69925 6.608079999999999 ZT16-19 4.101545 4.101545 4.101545 ZT20-23 3.51713 3.51713 3.51713