condition mean min max ZT0-3 28.663575 25.3703 31.95685 ZT4-7 17.37595 17.37595 17.37595 ZT8-11 12.61235 12.61235 12.61235 ZT12-15 0 0 0 ZT16-19 23.51215 23.51215 23.51215 ZT20-23 20.90815 20.90815 20.90815