condition mean min max ZT0-3 1.7580916666666668 1.50536 2.25287 ZT4-7 1.165605 1.165605 1.165605 ZT8-11 2.65245 2.65245 2.65245 ZT12-15 2.31491 1.9246 2.7052199999999997 ZT16-19 1.2687265 1.2687265 1.2687265 ZT20-23 1.2125139999999999 1.2125139999999999 1.2125139999999999