condition mean min max ZT0-3 9.567695 9.567695 9.567695 ZT4-7 6.855029999999999 6.855029999999999 6.855029999999999 ZT8-11 6.94264 6.94264 6.94264 ZT12-15 8.740680000000001 8.740680000000001 8.740680000000001 ZT16-19 11.58325 11.58325 11.58325 ZT20-23 10.494965 10.494965 10.494965