condition mean min max ZT0-3 1.102925 0.884591 1.35458 ZT4-7 0.6339984999999999 0.6339984999999999 0.6339984999999999 ZT8-11 0.7240475 0.7240475 0.7240475 ZT12-15 0.6882985 0.5591835 0.8174135 ZT16-19 0.521954 0.521954 0.521954 ZT20-23 0.4908555 0.4908555 0.4908555