condition mean min max ZT0-3 3.796175 2.79485 4.5006 ZT4-7 4.305975 4.305975 4.305975 ZT8-11 1.68429 1.68429 1.68429 ZT12-15 1.05204375 0.942273 1.1618145 ZT16-19 1.4436849999999999 1.4436849999999999 1.4436849999999999 ZT20-23 1.977225 1.977225 1.977225