condition mean min max ZT0-3 2.6322975 2.3656800000000002 2.8989149999999997 ZT4-7 3.2935049999999997 3.2935049999999997 3.2935049999999997 ZT8-11 2.79827 2.79827 2.79827 ZT12-15 0 0 0 ZT16-19 3.317625 3.317625 3.317625 ZT20-23 3.041795 3.041795 3.041795