condition mean min max ZT0-3 2.6294375 2.08153 3.177345 ZT4-7 3.103005 3.103005 3.103005 ZT8-11 3.3758049999999997 3.3758049999999997 3.3758049999999997 ZT12-15 0 0 0 ZT16-19 4.35228 4.35228 4.35228 ZT20-23 5.654005 5.654005 5.654005