condition mean min max ZT0-3 2.71691 2.55618 3.03484 ZT4-7 1.511435 1.511435 1.511435 ZT8-11 1.21009 1.21009 1.21009 ZT12-15 1.22328125 0.7666075 1.679955 ZT16-19 1.3926910000000001 1.3926910000000001 1.3926910000000001 ZT20-23 2.396745 2.396745 2.396745