condition mean min max ZT0-3 2.1754724999999997 2.091035 2.2599099999999996 ZT4-7 1.98915 1.98915 1.98915 ZT8-11 2.36737 2.36737 2.36737 ZT12-15 0 0 0 ZT16-19 2.35382 2.35382 2.35382 ZT20-23 1.915705 1.915705 1.915705