condition mean min max ZT0-3 8.1 8.1 8.1 ZT4-7 24.4 24.4 24.4 ZT8-11 13.4 13.4 13.4 ZT12-15 11.0 11.0 11.0 ZT16-19 14.2 14.2 14.2 ZT20-23 9.25 9.25 9.25