condition mean min max ZT0-3 8.948263 8.948263 8.948263 ZT4-7 9.016247499999999 9.016247499999999 9.016247499999999 ZT8-11 7.8504305 7.8504305 7.8504305 ZT12-15 8.414833999999999 8.414833999999999 8.414833999999999 ZT16-19 9.1499655 9.1499655 9.1499655 ZT20-23 9.4157685 9.4157685 9.4157685