condition mean min max ZT0-3 5.1605975 4.964405 5.35679 ZT4-7 8.181725 8.181725 8.181725 ZT8-11 11.174399999999999 11.174399999999999 11.174399999999999 ZT12-15 0 0 0 ZT16-19 10.8309 10.8309 10.8309 ZT20-23 8.00418 8.00418 8.00418