condition mean min max ZT0-3 8.303916666666666 6.168635 10.197905 ZT4-7 6.939475 6.939475 6.939475 ZT8-11 8.511 8.511 8.511 ZT12-15 8.6173275 8.494695 8.73996 ZT16-19 9.12851 9.12851 9.12851 ZT20-23 12.19895 12.19895 12.19895