condition mean min max ZT0-3 267.131367 267.131367 267.131367 ZT4-7 336.4238015 336.4238015 336.4238015 ZT8-11 372.90103899999997 372.90103899999997 372.90103899999997 ZT12-15 364.148413 364.148413 364.148413 ZT16-19 549.0016035 549.0016035 549.0016035 ZT20-23 512.3059384999999 512.3059384999999 512.3059384999999