condition mean min max ZT0-3 3.5890983333333333 2.66561 4.0797799999999995 ZT4-7 2.5903 2.5903 2.5903 ZT8-11 2.841175 2.841175 2.841175 ZT12-15 4.562430000000001 4.228575 4.896285000000001 ZT16-19 4.132165 4.132165 4.132165 ZT20-23 5.15245 5.15245 5.15245