condition mean min max ZT0-3 4.394775 4.394775 4.394775 ZT4-7 1.9509 1.9509 1.9509 ZT8-11 3.767815 3.767815 3.767815 ZT12-15 3.53704 3.53704 3.53704 ZT16-19 5.05547 5.05547 5.05547 ZT20-23 4.126715 4.126715 4.126715