condition mean min max ZT0-3 3.159523333333333 3.159523333333333 3.159523333333333 ZT4-7 1.568885 1.568885 1.568885 ZT8-11 0.8173954999999999 0.8173954999999999 0.8173954999999999 ZT12-15 1.234424 1.234424 1.234424 ZT16-19 2.47433 2.47433 2.47433 ZT20-23 2.92286 2.92286 2.92286