condition mean min max ZT0-3 18.8643 16.604599999999998 21.124000000000002 ZT4-7 16.404899999999998 16.404899999999998 16.404899999999998 ZT8-11 21.9115 21.9115 21.9115 ZT12-15 32.57268333333333 29.756066666666666 35.3893 ZT16-19 38.2556 38.2556 38.2556 ZT20-23 31.7283 31.7283 31.7283