condition mean min max ZT0-3 9.682395 4.616215 18.31645 ZT4-7 12.9727 12.9727 12.9727 ZT8-11 2.72051 2.72051 2.72051 ZT12-15 3.34405 2.73549 3.95261 ZT16-19 2.2262399999999998 2.2262399999999998 2.2262399999999998 ZT20-23 1.6250499999999999 1.6250499999999999 1.6250499999999999