condition mean min max ZT0-3 4.5556675 3.875995 5.235340000000001 ZT4-7 5.620955 5.620955 5.620955 ZT8-11 4.66292 4.66292 4.66292 ZT12-15 0 0 0 ZT16-19 4.77346 4.77346 4.77346 ZT20-23 4.50516 4.50516 4.50516