condition mean min max ZT0-3 5.505986666666666 0.0 8.44136 ZT4-7 20.47965 20.47965 20.47965 ZT8-11 8.2946 8.2946 8.2946 ZT12-15 2.0750575 0.0 4.150115 ZT16-19 11.769884999999999 11.769884999999999 11.769884999999999 ZT20-23 8.906585 8.906585 8.906585