condition mean min max ZT0-3 9.75 9.75 9.75 ZT4-7 29.5 29.5 29.5 ZT8-11 12.450000000000001 12.450000000000001 12.450000000000001 ZT12-15 7.1 7.1 7.1 ZT16-19 16.9 16.9 16.9 ZT20-23 11.65 11.65 11.65