condition mean min max ZT0-3 6.75 6.75 6.75 ZT4-7 6.4 6.4 6.4 ZT8-11 33.4 33.4 33.4 ZT12-15 18.85 18.85 18.85 ZT16-19 7.1 7.1 7.1 ZT20-23 9.600000000000001 9.600000000000001 9.600000000000001