condition mean min max ZT0-3 3.65078 3.65078 3.65078 ZT4-7 8.440345 8.440345 8.440345 ZT8-11 3.5447949999999997 3.5447949999999997 3.5447949999999997 ZT12-15 3.770455 3.770455 3.770455 ZT16-19 5.73043 5.73043 5.73043 ZT20-23 2.73276 2.73276 2.73276