condition mean min max ZT0-3 21.03915 21.03915 21.03915 ZT4-7 16.21985 16.21985 16.21985 ZT8-11 12.1801 12.1801 12.1801 ZT12-15 13.0047 13.0047 13.0047 ZT16-19 17.2207 17.2207 17.2207 ZT20-23 21.7425 21.7425 21.7425