condition mean min max ZT0-3 2.9 2.9 2.9 ZT4-7 2.4 2.4 2.4 ZT8-11 8.7 8.7 8.7 ZT12-15 16.349999999999998 16.349999999999998 16.349999999999998 ZT16-19 9.55 9.55 9.55 ZT20-23 22.200000000000003 22.200000000000003 22.200000000000003