condition mean min max ZT0-3 2.769645 2.657535 2.881755 ZT4-7 3.955675 3.955675 3.955675 ZT8-11 4.020235 4.020235 4.020235 ZT12-15 0 0 0 ZT16-19 3.877595 3.877595 3.877595 ZT20-23 4.1381 4.1381 4.1381