condition mean min max ZT0-3 0.0 0.0 0.0 ZT4-7 0.0 0.0 0.0 ZT8-11 0.0 0.0 0.0 ZT12-15 1.6946725 0.0 3.389345 ZT16-19 2.961765 2.961765 2.961765 ZT20-23 3.33971 3.33971 3.33971