condition mean min max ZT0-3 5.65 5.65 5.65 ZT4-7 5.4 5.4 5.4 ZT8-11 5.0 5.0 5.0 ZT12-15 6.35 6.35 6.35 ZT16-19 5.0 5.0 5.0 ZT20-23 5.15 5.15 5.15