condition mean min max ZT0-3 211.693595 211.693595 211.693595 ZT4-7 160.786179 160.786179 160.786179 ZT8-11 317.77203499999996 317.77203499999996 317.77203499999996 ZT12-15 496.4685195 496.4685195 496.4685195 ZT16-19 613.023182 613.023182 613.023182 ZT20-23 1230.0442855 1230.0442855 1230.0442855