condition mean min max ZT0-3 5.666035 5.05647 6.2756 ZT4-7 3.04555 3.04555 3.04555 ZT8-11 3.033035 3.033035 3.033035 ZT12-15 0 0 0 ZT16-19 6.07757 6.07757 6.07757 ZT20-23 7.073275 7.073275 7.073275