condition mean min max ZT0-3 21.115651 21.115651 21.115651 ZT4-7 14.566348 14.566348 14.566348 ZT8-11 17.0213565 17.0213565 17.0213565 ZT12-15 17.998106 17.998106 17.998106 ZT16-19 15.1965725 15.1965725 15.1965725 ZT20-23 15.354433499999999 15.354433499999999 15.354433499999999