condition mean min max ZT0-3 15.702625 14.29655 17.1087 ZT4-7 13.6981 13.6981 13.6981 ZT8-11 8.980785000000001 8.980785000000001 8.980785000000001 ZT12-15 0 0 0 ZT16-19 21.8082 21.8082 21.8082 ZT20-23 18.97405 18.97405 18.97405