condition mean min max ZT0-3 4.503805 4.05149 4.864335 ZT4-7 2.57171 2.57171 2.57171 ZT8-11 4.426805 4.426805 4.426805 ZT12-15 6.669605 6.46181 6.8774 ZT16-19 5.162255 5.162255 5.162255 ZT20-23 6.077635000000001 6.077635000000001 6.077635000000001