condition mean min max ZT0-3 3.1457283333333335 1.833745 3.975845 ZT4-7 1.0139395 1.0139395 1.0139395 ZT8-11 1.474205 1.474205 1.474205 ZT12-15 2.5345725 2.0506349999999998 3.01851 ZT16-19 3.1789300000000003 3.1789300000000003 3.1789300000000003 ZT20-23 3.74768 3.74768 3.74768