condition mean min max ZT0-3 6.184328333333333 4.6249649999999995 7.035415 ZT4-7 4.616725 4.616725 4.616725 ZT8-11 4.013795 4.013795 4.013795 ZT12-15 4.8420925 4.325934999999999 5.35825 ZT16-19 4.513595 4.513595 4.513595 ZT20-23 7.045745 7.045745 7.045745