condition mean min max ZT0-3 4.793965 4.793965 4.793965 ZT4-7 4.497045 4.497045 4.497045 ZT8-11 4.23841 4.23841 4.23841 ZT12-15 3.513675 3.513675 3.513675 ZT16-19 5.08187 5.08187 5.08187 ZT20-23 4.710075 4.710075 4.710075