condition mean min max ZT0-3 14.6988 14.6988 14.6988 ZT4-7 15.200050000000001 15.200050000000001 15.200050000000001 ZT8-11 11.7775 11.7775 11.7775 ZT12-15 12.317699999999999 12.317699999999999 12.317699999999999 ZT16-19 12.9093 12.9093 12.9093 ZT20-23 13.1034 13.1034 13.1034