condition mean min max ZT0-3 1.963505 1.963505 1.963505 ZT4-7 0.609579 0.609579 0.609579 ZT8-11 0.2482515 0.2482515 0.2482515 ZT12-15 0.3669525 0.3669525 0.3669525 ZT16-19 0.662603 0.662603 0.662603 ZT20-23 1.24959 1.24959 1.24959