condition mean min max ZT0-3 19.844075 19.73375 19.9544 ZT4-7 18.291249999999998 18.291249999999998 18.291249999999998 ZT8-11 18.01455 18.01455 18.01455 ZT12-15 0 0 0 ZT16-19 26.9839 26.9839 26.9839 ZT20-23 24.46545 24.46545 24.46545