condition mean min max ZT0-3 18.748948333333335 10.976495 24.544249999999998 ZT4-7 8.988205 8.988205 8.988205 ZT8-11 12.323550000000001 12.323550000000001 12.323550000000001 ZT12-15 21.811625 17.839550000000003 25.7837 ZT16-19 24.01245 24.01245 24.01245 ZT20-23 29.82055 29.82055 29.82055