condition mean min max ZT0-3 4.24634 4.24634 4.24634 ZT4-7 4.470315 4.470315 4.470315 ZT8-11 2.90867 2.90867 2.90867 ZT12-15 2.6835649999999998 2.6835649999999998 2.6835649999999998 ZT16-19 3.3134333333333332 3.3134333333333332 3.3134333333333332 ZT20-23 3.9338100000000003 3.9338100000000003 3.9338100000000003