condition mean min max ZT0-3 11.7 11.7 11.7 ZT4-7 13.8 13.8 13.8 ZT8-11 11.25 11.25 11.25 ZT12-15 25.450000000000003 25.450000000000003 25.450000000000003 ZT16-19 10.15 10.15 10.15 ZT20-23 6.1 6.1 6.1