condition mean min max ZT0-3 3.805735 3.182175 4.46841 ZT4-7 4.366795 4.366795 4.366795 ZT8-11 1.418135 1.418135 1.418135 ZT12-15 0.856786 0.769895 0.943677 ZT16-19 1.28941 1.28941 1.28941 ZT20-23 1.652695 1.652695 1.652695