condition mean min max ZT0-3 3.058565 2.38032 3.73681 ZT4-7 1.123505 1.123505 1.123505 ZT8-11 2.04149 2.04149 2.04149 ZT12-15 0 0 0 ZT16-19 1.207739 1.207739 1.207739 ZT20-23 2.48137 2.48137 2.48137