condition mean min max ZT0-3 8.65 8.65 8.65 ZT4-7 6.6 6.6 6.6 ZT8-11 8.85 8.85 8.85 ZT12-15 14.45 14.45 14.45 ZT16-19 22.200000000000003 22.200000000000003 22.200000000000003 ZT20-23 24.85 24.85 24.85