condition mean min max ZT0-3 6.45 6.45 6.45 ZT4-7 5.9 5.9 5.9 ZT8-11 30.15 30.15 30.15 ZT12-15 16.150000000000002 16.150000000000002 16.150000000000002 ZT16-19 13.65 13.65 13.65 ZT20-23 6.75 6.75 6.75