condition mean min max ZT0-3 23.37777778 23.37777778 23.37777778 ZT4-7 19.849999999999998 19.849999999999998 19.849999999999998 ZT8-11 21.17 21.17 21.17 ZT12-15 30.972222223333333 30.972222223333333 30.972222223333333 ZT16-19 29.28444444333333 29.28444444333333 29.28444444333333 ZT20-23 30.30111111 30.30111111 30.30111111