condition mean min max ZT0-3 3.9154025 2.871625 4.95918 ZT4-7 7.739805 7.739805 7.739805 ZT8-11 5.505095 5.505095 5.505095 ZT12-15 0 0 0 ZT16-19 8.883495 8.883495 8.883495 ZT20-23 12.03405 12.03405 12.03405