condition mean min max ZT0-3 3.278331666666667 1.71915 4.07558 ZT4-7 2.433185 2.433185 2.433185 ZT8-11 1.959605 1.959605 1.959605 ZT12-15 2.8576224999999997 2.509505 3.2057399999999996 ZT16-19 2.7790850000000002 2.7790850000000002 2.7790850000000002 ZT20-23 4.59232 4.59232 4.59232