condition mean min max ZT0-3 20.328405 20.328405 20.328405 ZT4-7 23.664296999999998 23.664296999999998 23.664296999999998 ZT8-11 30.375537 30.375537 30.375537 ZT12-15 29.3338105 29.3338105 29.3338105 ZT16-19 39.456875 39.456875 39.456875 ZT20-23 29.2595175 29.2595175 29.2595175