condition mean min max ZT0-3 6.272935 6.272935 6.272935 ZT4-7 4.7526399999999995 4.7526399999999995 4.7526399999999995 ZT8-11 5.60477 5.60477 5.60477 ZT12-15 7.02005 7.02005 7.02005 ZT16-19 7.47101 7.47101 7.47101 ZT20-23 6.89935 6.89935 6.89935