condition mean min max ZT0-3 11.28062623 11.149652 11.411600459999999 ZT4-7 7.53433229625 6.830387838 8.2382767545 ZT8-11 6.0345535125 5.103817642499999 6.9652893825 ZT12-15 8.3680206565 7.940550355999999 8.795490957 ZT16-19 7.0164398165 6.5063332625 7.5265463705 ZT20-23 8.28101883475 7.45412269 9.1079149795