condition mean min max ZT0-3 3.146135 2.86902 3.42325 ZT4-7 3.218615 3.218615 3.218615 ZT8-11 2.52665 2.52665 2.52665 ZT12-15 0 0 0 ZT16-19 3.9877249999999997 3.9877249999999997 3.9877249999999997 ZT20-23 4.06383 4.06383 4.06383