condition mean min max ZT0-3 3.310035 2.82511 3.79496 ZT4-7 2.6528 2.6528 2.6528 ZT8-11 4.35313 4.35313 4.35313 ZT12-15 0 0 0 ZT16-19 4.390095 4.390095 4.390095 ZT20-23 4.29918 4.29918 4.29918