condition mean min max ZT0-3 26.349999999999998 26.349999999999998 26.349999999999998 ZT4-7 17.7 17.7 17.7 ZT8-11 15.9 15.9 15.9 ZT12-15 18.8 18.8 18.8 ZT16-19 12.1 12.1 12.1 ZT20-23 8.95 8.95 8.95