condition mean min max ZT0-3 11.224198 11.224198 11.224198 ZT4-7 11.6757615 11.6757615 11.6757615 ZT8-11 10.837309999999999 10.837309999999999 10.837309999999999 ZT12-15 9.9406835 9.9406835 9.9406835 ZT16-19 10.928899000000001 10.928899000000001 10.928899000000001 ZT20-23 10.933482999999999 10.933482999999999 10.933482999999999