condition mean min max ZT0-3 2.368030666666667 2.368030666666667 2.368030666666667 ZT4-7 2.092185 2.092185 2.092185 ZT8-11 1.0675949999999998 1.0675949999999998 1.0675949999999998 ZT12-15 1.35427 1.35427 1.35427 ZT16-19 3.17358 3.17358 3.17358 ZT20-23 1.997821 1.997821 1.997821