condition mean min max ZT0-3 1.7915933333333334 1.6675 2.025175 ZT4-7 3.4020650000000003 3.4020650000000003 3.4020650000000003 ZT8-11 12.965250000000001 12.965250000000001 12.965250000000001 ZT12-15 7.147235 7.14308 7.151389999999999 ZT16-19 12.6677 12.6677 12.6677 ZT20-23 10.692810000000001 10.692810000000001 10.692810000000001