condition mean min max ZT0-3 8.1 8.1 8.1 ZT4-7 27.3 27.3 27.3 ZT8-11 39.55 39.55 39.55 ZT12-15 10.4 10.4 10.4 ZT16-19 10.600000000000001 10.600000000000001 10.600000000000001 ZT20-23 33.7 33.7 33.7