condition mean min max ZT0-3 21.299999999999997 21.299999999999997 21.299999999999997 ZT4-7 19.2 19.2 19.2 ZT8-11 11.7 11.7 11.7 ZT12-15 18.75 18.75 18.75 ZT16-19 12.600000000000001 12.600000000000001 12.600000000000001 ZT20-23 28.45 28.45 28.45