condition mean min max ZT0-3 1.655815 1.629385 1.682245 ZT4-7 2.23376 2.23376 2.23376 ZT8-11 2.777505 2.777505 2.777505 ZT12-15 0 0 0 ZT16-19 2.52539 2.52539 2.52539 ZT20-23 2.508225 2.508225 2.508225