condition mean min max ZT0-3 0.470165 0.0 1.410495 ZT4-7 2.68523 2.68523 2.68523 ZT8-11 6.79725 6.79725 6.79725 ZT12-15 2.763465 1.327125 4.199805 ZT16-19 3.906105 3.906105 3.906105 ZT20-23 4.352774999999999 4.352774999999999 4.352774999999999