condition mean min max ZT0-3 5.050000000000001 5.050000000000001 5.050000000000001 ZT4-7 17.9 17.9 17.9 ZT8-11 38.5 38.5 38.5 ZT12-15 6.4 6.4 6.4 ZT16-19 6.2 6.2 6.2 ZT20-23 13.3 13.3 13.3