condition mean min max ZT0-3 5.45 5.45 5.45 ZT4-7 5.6 5.6 5.6 ZT8-11 7.75 7.75 7.75 ZT12-15 11.7 11.7 11.7 ZT16-19 11.7 11.7 11.7 ZT20-23 6.4 6.4 6.4