condition mean min max ZT0-3 8.365738333333333 3.846035 12.04535 ZT4-7 3.15749 3.15749 3.15749 ZT8-11 3.02205 3.02205 3.02205 ZT12-15 5.668715000000001 4.905865 6.431565 ZT16-19 6.90721 6.90721 6.90721 ZT20-23 10.8232 10.8232 10.8232