condition mean min max ZT0-3 6.19763 6.19763 6.19763 ZT4-7 5.49765 5.49765 5.49765 ZT8-11 4.3770050000000005 4.3770050000000005 4.3770050000000005 ZT12-15 7.07888 7.07888 7.07888 ZT16-19 4.932035 4.932035 4.932035 ZT20-23 6.5145 6.5145 6.5145