condition mean min max ZT0-3 7.707495 7.589735 7.863055 ZT4-7 4.826945 4.826945 4.826945 ZT8-11 5.106825000000001 5.106825000000001 5.106825000000001 ZT12-15 4.4779875 4.2038400000000005 4.752135 ZT16-19 4.574014999999999 4.574014999999999 4.574014999999999 ZT20-23 8.388935 8.388935 8.388935