condition mean min max ZT0-3 18.30469 18.30469 18.30469 ZT4-7 16.654215 16.654215 16.654215 ZT8-11 18.0425415 18.0425415 18.0425415 ZT12-15 17.9934255 17.9934255 17.9934255 ZT16-19 17.7595605 17.7595605 17.7595605 ZT20-23 15.311916 15.311916 15.311916