condition mean min max ZT0-3 26.25 26.25 26.25 ZT4-7 8.7 8.7 8.7 ZT8-11 7.65 7.65 7.65 ZT12-15 39.75 39.75 39.75 ZT16-19 11.850000000000001 11.850000000000001 11.850000000000001 ZT20-23 29.45 29.45 29.45