condition mean min max ZT0-3 21.937691 21.937691 21.937691 ZT4-7 14.481584999999999 14.481584999999999 14.481584999999999 ZT8-11 18.507902 18.507902 18.507902 ZT12-15 19.927978500000002 19.927978500000002 19.927978500000002 ZT16-19 21.3685285 21.3685285 21.3685285 ZT20-23 18.3005445 18.3005445 18.3005445