condition mean min max ZT0-3 8.797285 8.797285 8.797285 ZT4-7 5.861025 5.861025 5.861025 ZT8-11 5.90274 5.90274 5.90274 ZT12-15 7.245115 7.245115 7.245115 ZT16-19 9.39401 9.39401 9.39401 ZT20-23 8.62336 8.62336 8.62336