condition mean min max ZT0-3 5.794175 5.794175 5.794175 ZT4-7 3.904355 3.904355 3.904355 ZT8-11 4.871135 4.871135 4.871135 ZT12-15 7.07452 7.07452 7.07452 ZT16-19 7.79247 7.79247 7.79247 ZT20-23 7.52156 7.52156 7.52156