condition mean min max ZT0-3 2.1197 2.086615 2.1527849999999997 ZT4-7 2.534925 2.534925 2.534925 ZT8-11 2.51776 2.51776 2.51776 ZT12-15 0 0 0 ZT16-19 3.835165 3.835165 3.835165 ZT20-23 3.95449 3.95449 3.95449