condition mean min max ZT0-3 20.237211 20.237211 20.237211 ZT4-7 18.4855665 18.4855665 18.4855665 ZT8-11 16.6792405 16.6792405 16.6792405 ZT12-15 14.5700135 14.5700135 14.5700135 ZT16-19 13.4435575 13.4435575 13.4435575 ZT20-23 14.7371695 14.7371695 14.7371695