condition mean min max ZT0-3 3.350605 3.350605 3.350605 ZT4-7 3.888605 3.888605 3.888605 ZT8-11 4.51794 4.51794 4.51794 ZT12-15 4.211145 4.211145 4.211145 ZT16-19 4.94721 4.94721 4.94721 ZT20-23 1.38035 1.38035 1.38035