condition mean min max ZT0-3 2.23642 2.23642 2.23642 ZT4-7 2.02741 2.02741 2.02741 ZT8-11 1.53514 1.53514 1.53514 ZT12-15 1.43242 1.43242 1.43242 ZT16-19 2.51569 2.51569 2.51569 ZT20-23 1.514775 1.514775 1.514775