condition mean min max ZT0-3 13.15 13.15 13.15 ZT4-7 9.1 9.1 9.1 ZT8-11 12.1 12.1 12.1 ZT12-15 8.4 8.4 8.4 ZT16-19 13.0 13.0 13.0 ZT20-23 11.9 11.9 11.9