condition mean min max ZT0-3 19.232525 16.14305 22.322 ZT4-7 47.3368 47.3368 47.3368 ZT8-11 21.7035 21.7035 21.7035 ZT12-15 0 0 0 ZT16-19 20.58345 20.58345 20.58345 ZT20-23 16.82555 16.82555 16.82555