condition mean min max ZT0-3 6.685136666666667 1.79334 9.449995 ZT4-7 2.567975 2.567975 2.567975 ZT8-11 1.962475 1.962475 1.962475 ZT12-15 2.91494 1.792105 4.037775 ZT16-19 5.562495 5.562495 5.562495 ZT20-23 10.4728 10.4728 10.4728