condition mean min max ZT0-3 9.597456 9.597456 9.597456 ZT4-7 7.463412 7.463412 7.463412 ZT8-11 8.4287525 8.4287525 8.4287525 ZT12-15 8.894401 8.894401 8.894401 ZT16-19 9.0687775 9.0687775 9.0687775 ZT20-23 9.0140915 9.0140915 9.0140915