condition mean min max ZT0-3 9.578584 9.578584 9.578584 ZT4-7 10.083108 10.083108 10.083108 ZT8-11 8.957252 8.957252 8.957252 ZT12-15 9.256200499999998 9.256200499999998 9.256200499999998 ZT16-19 9.3490675 9.3490675 9.3490675 ZT20-23 8.872852 8.872852 8.872852