condition mean min max ZT0-3 3.4041476192499998 3.3141627744999997 3.4941324639999998 ZT4-7 2.20748803025 2.151491532 2.2634845285 ZT8-11 3.46097574525 2.727176374 4.1947751165 ZT12-15 4.73691087425 4.0067732945 5.467048454 ZT16-19 4.78126531725 4.001695951 5.5608346835 ZT20-23 8.59833454375 7.443263128 9.7534059595