condition mean min max ZT0-3 4.217505 4.217505 4.217505 ZT4-7 4.05806 4.05806 4.05806 ZT8-11 4.934225 4.934225 4.934225 ZT12-15 5.28724 5.28724 5.28724 ZT16-19 5.550025 5.550025 5.550025 ZT20-23 4.35867 4.35867 4.35867