condition mean min max ZT0-3 316.6464629 265.3693759 367.9235499 ZT4-7 131.8716671675 104.08850723500001 159.6548271 ZT8-11 76.625763125 53.904745430000006 99.34678082 ZT12-15 7.518867780000001 2.133056436 12.904679124000001 ZT16-19 2.7425410465 2.4845654990000003 3.0005165939999996 ZT20-23 0.7307854695 0.368104314 1.093466625