condition mean min max ZT0-3 255.539749 255.539749 255.539749 ZT4-7 191.0252205 191.0252205 191.0252205 ZT8-11 229.72806149999997 229.72806149999997 229.72806149999997 ZT12-15 316.701239 316.701239 316.701239 ZT16-19 276.8445225 276.8445225 276.8445225 ZT20-23 266.5714885 266.5714885 266.5714885