condition mean min max ZT0-3 4.452785 3.2568 6.519080000000001 ZT4-7 11.21339 11.21339 11.21339 ZT8-11 9.992255 9.992255 9.992255 ZT12-15 20.18545 19.5512 20.819699999999997 ZT16-19 14.74455 14.74455 14.74455 ZT20-23 10.365649999999999 10.365649999999999 10.365649999999999